texts: Light Strip with ESP8266 and ZigBee for HUE Bridge

texts:
I currently have an ESP8266, which controlls my WS2812b light strip.

I want to add it to my current Hue  setup(1 Bridge, 4 Lamps). I know that I'll need a ZigBee module of some sort. Are there any I can add to my esp and then decide if I want to use the commands the hue sent me or if I want to manually control the light strip?

Do you know of any compatible ZigBee devices?


texts: A question about negative phase angles in Bode plots

texts:
Looking at the phase Bode plot for the output of a filter as shown below:

1-) Taking the point -460° as an example, can we say that this is equivalent to +100°?
2-) Does that mean the output signal is leading the input signal by 100°?


texts: How should endpoint report error for TLP over PCI Express (PCIe)?

texts:
On a Windows system there is a PCI Express (PCIe) endpoint device with an application design that handles TLPs from Windows.
The design is being updated, and I want to leave out some previous functionality, that I expect is unused.
However, I want to generate an error back to Windows if the application design receives a TLP that tries to access some of the left out functionality, so I can detect this problem.
Both posted (write) and non-posted (read) TLPs could potentially access such left out functionality, so error reporting should be possible for both types of TLPs.
Added: There existing application SW on Windows should be able to run without modifications, and when the design is complete, no errors should be generated due to access to removed features.
What is the best way to generate error back to Windows in this case?


texts: How can I make a log amplifier's logarithmic region span across the range of 0-5V input instead just working close to 0V?

texts: I need to implement a log amplifier. Currently I'm doing it using a diode in the negative feedback loop but it only really gives me the log response close to the zero input, with the amps output quickly becoming proportional to the input (around 0.2V). Is there a way to make this logarithmic region span the entire length of the 0-5V input domain?


texts: Solid state relay for home lights application

texts:
My application is controlling home lights. I want to use relays to switch lights on and off. My circuit should work on all kind of lights such as neon lights, halogen lights, strobe lights and others. I should decide what kind of relay I have to use, EMR or SSR. I have read about solid state relays and I encountered two issues.

First, I know one of the limitations of the SSR is the leakage current. If it is 5 mA for example, the neon light my not turn completely off. The leakage current may be sufficient to keep the light on. Right?

Second, some types of strobe lights incorporate a diode in series with the coil or filament. This causes the light to behave as a half-wave rectifier. There is an RC circuit in parallel with the output of SSR. The capacitor in this circuit cannot discharge through the series diode, causing a voltage to appear across the SSR terminals. I know that SSR must see a zero voltage across the terminals to come on, it can’t turn on again in this situation. Right?

what is your final recommendation for my specific application. I am not really concerned about the life time because typically the number of contacts may not exceed 10 per day


texts: Recharging a lipo battery while using it

texts:
Right now I am designing a circuit that will charge a lipo battery via usb, using the mcp73831 (at 100mA).
The battery voltage(nominal 3.7v) will be regulated to 3.3v to power a microcontroller like an attiny85 or esp8266 for example.
Below is what I have so far, my question is: Are there any flaws/mistakes I made, and how can I charge the lipo battery while simultaneously powering the mcu? Because right now I can only charge OR use the mcu, depending on the spdt switch.


texts:
I am working on a project which will be switching LED strips with a max of 2A.
As a test I have connected a 20W hallogen light. When I try to switch it I get a voltage drop as can be seen in the scope picture and causes my microcontroller to reboot (< 5V). I was thinking of using a capacitor to filter out the voltage drop.

How can I determine which value of capacitor I can use? Or does someone have any other tip I can do to fix this?

simulate this circuit – Schematic created using CircuitLab


texts:
I'm trying to learn PCB design and, from what I've read and seen, there appear to be three different types of vias:

Through hole - goes all the way through the board
Blind - goes from the top or bottom layer to some layer in between the top and bottom, but not all the way through
Buried - is between the top and bottom layers

It seems like most semi-complex boards I've had the opportunity to look at are 4-layer boards, and that usually one layer is dedicated to GND, another to VCC, and then the other two have traces. My question is what kind of via is most appropriate when trying to connect a pad or trace from one layer to the GND or VCC layers? I ask because I would have thought that a blind or buried via should be used, but it seems like most boards I've looked at use through hole vias and that there's just a stop around the via on the layers it's not supposed to be connected to. Is there a reason to use that method instead of using a blind or buried via?


texts: Is a 14((n^2)÷2) gate n-bit integer divider reasonable?

texts:
I figured a way to implement a fast divider (basically a ripple-carry divider) with deterministic delay, but it's stupidly-large, essentially requiring two AND gates (multiplier and a position test to line up the divisor and the dividend properly) and a full adder for half of n×n (to add the results of multiplication).  It's essentially a combinational (i.e. unrolled) implementation of the below algorithm by Jain, Pancholi, Garg, and Saini:

In practice, the circuit would quickly grow so large as to have a relatively-high delay, so would be broken down into stages to avoid a low clock rate in e.g. a CPU or ALU.  By pipelining the divider, you can put in one input per clock, and obtain a deterministic output with quotient and remainder once per clock; whereas if you're saving area, it wouldn't be pipelined, but would be a state machine and would remain busy until finished with the single division calculation several clock cycles later.

A single stage is two AND gates and a full adder for each bit of output, plus intermediate register to maintain state; a single asynchronous circuit has what amounts to ever-shorter horizontal ripple carry dividers at each stage feeding a vertical ripple-carry divider, so has the delay of e.g. a 64-bit ripple carry adder for 64x64 division.  This doesn't seem to justify having what amounts to 64 ripple-carry adders running in parallel (at stage m, you need (n-m) full adders horizontally, and n-(n-m) full adders vertically).

The critical path would be 2 ripple-carry adders:

           1          2          3
X X X X X  C X X X X  C C X X X  C C C X X
  X X X X    X X X X    X X X X    C X X X
    X X X      X X X      X X X      X X X
      X X        X X        X X        X X
        X          X          X          X

4          5          6          7
C C C C X  C C C C C  C C C C C  C C C C C
  C C X X    C C C X    C C C C    C C C C
    X X X      C X X      C C X      C C C
      X X        X X        X X        C X
        X          X          X          X

8          9
C C C C C  C C C C C
  C C C C    C C C C
    C C C      C C C
      C C        C C
        X          C

It's still huge.  Does anyone even use integer division?  Is a combinational approach worthwhile, or is an iterative approach better for a general-purpose CPU?


texts:
I would like to have more PCIe slots, and ideally I would like for them to be external to the computer.

What I think I am looking for is then a combination of PCIe extender (for additional slots) and riser (for external).

I have found something like this amazon but I am a bit skeptical because I can't really find it on electronics shops like Digikey etc...

I have a few questions on this, pardon my ignorance:

the computer end of the slot is a PCIe x1, while the others can go up to x16... How's that possible? Is there no consequence to not connecting to the full x16 slot on the computer side?
Is speed (or other) affected by having a USB cable between the computer end and the extender?
Are these things not standard? Is this why I can only find them on ebay and amazon?


texts: Why are ALE and INTA not floated during Hold on an 8088 while other outputs are?

texts:
When the 8088 goes into hold, every output is tri-stated apart from HLDA (obviously), ALE and INTA. Given that the purpose of hold is to allow an external device to control the bus, like a DMA controller, what's the rationale behind ALE and INTA still being driven?
I think I partly know the answer to this:
If INTA (which normally isn't connected to another bus controller) wasn't driven high, it might float low and accidentally cause an interrupt vector to be placed onto the data bus causing contention.
If ALE wasn't driven low, it might float high and accidentally latch some spurious low-order address data, so that when the CPU came out of hold then A0..A7 would be incorrect. But this wouldn't matter, would it? As after exiting hold the next instruction's T1 cycle would cause the correct low-order address lines to be latched.
Is it simply that ALE doesn't NEED to be tri-stated?


texts:
How can I find Gain margin of any control system given its polar plot In schaum's series I have read that Gain Margin=Ku/Ki but in given figure the system never becomes unstable so shouldn't Gain margin be infinity.

Also should the gain margin of the above system be infinite


texts: Power transformer question in vacuum tube circuit

texts:
I am having trouble wrapping my brain around this power transformer circuit. I must be missing something very fundamental, so I apologize in advance for that.

Can someone explain to me why the center tap on this schematic does not have to be rectified? Also, if the center tap is 0v, how is it supplying power? It appears to be powering all of the tubes except the final 807s. The transformer is a 300v. I'm not sure if that means 150-0-150, or 300-0-300.

I must be missing something simple.


texts: I found this oscillator schematic and I hope to find more information about it.


texts:
I have two logic signals that can be in two different configurations as shown in the image below.

I would like to output a third signal that is HIGH for case A and LOW for case B. How can I accomplish this?


texts: How do I connect digital logic components (eg. AND gate) to parts in a circuit?

texts:
This is meant to be part of a systems project I am required to complete. I want to create an alarm system using logic gates. For now, it basically involves:

INPUT: Lever, multiple detectors

This runs into an AND gate (consisting of digital NAND gate components) which then connects to:

OUTPUT: Alarm

How do I connect the NAND gates to each other and also to the lever and the alarm as a permanent circuit? I considered using breadboards, but they're only for temporary use. I heard a permanent solution may be through PCB, but I'm not sure how to go about it. Also any other options?

As you can probably tell, I am a newbie to this, so simple and concise explanations would be appreciated.


texts: Why constant current led driver is not used in parallel led strip?

texts:
I know that the constant current led driver is not used in the parallel led strip. and constant voltage led driver is not used in the series led strip.

can anyone explain me with the example that why this scenario is followed?

Thank you


texts:
I am currently in the process of trying to control an AC motor, but I am not sure of what the best way to go about it will be. My main issue is the lack of information I can find about the motor anywhere online.

This motor is a motor from a dryer.  The best information I can find is that it is a WE17M22, or a 5KH26GJ119T.  Here's an image of a very similar motor.  Besides that I cant really find much information on the motor, and I don't have a ton of ability to physically look at the motor itself, since it is well enclosed and running in a system.

The dryer that it would come in doesn't seem to have any speed controls, so I can't take any from that.  What do you think would be the easiest/cheapest way to control this motor?  Would something like a triac work for this, or does it need to be a more complex system?


texts:
For STM32F407 Discovery board how do I enable its FPU from CubeMX?

The following instruction is used in handwritten code. How can I get it generated from CubeMX?

// Enable FPU
  SCB->CPACR |= 0xf00000;


texts: SPI Flash - Unable to write to first 32 bytes in GD25Q128C

texts:
I am new to SPI flash memory reading and/or writing. As I was fiddling with it, I see that I cannot write to the first 32 bytes of the device GD25Q128C. It always reads back something that I have not written.
I have checked online and think that it could be due the first 32 bytes of every page is used for some other purpose?
I can successfully write and read from the remaining addresses.
Can somebody give more information on this?
Update:
It is the wikipedia that hints my assumption
Following image shows the logic analyzer capture for writing to first 32 bytes:
Following image shows the logic analyzer capture for writing after first 32 bytes:


texts:
Can anybody help me with the balance of the currents on the nodes A and B of the this picture?

Here is what I obtain:
At node A:
0.8 + V2/10 = 0.15 + V1/7.5 + i(B)
At node B:
i(B) + V3/10 = 0.8

The issue is that, considering the balance like this, 0.8 cancels (by substituting i(B) from the second equation to the first one). Where is the mistake? Could anybody help me please?


texts: Why a thermoelectric generator's efficiency increases when the thermal conductivity of thermoelectric materials decreases?

texts: A thermoelectric generator generates electricity from the flow of heat.The heat flow rate will increase if the thermal conductivity will increase. So the power generation should increase too. So why a thermoelectric generator's  efficiency increases when the thermal conductivity of thermoelectric materials decreases where the efficiency of the thermoelectric generator should be proportional to the thermal conductivity of thermoelectric materials?


texts: Solving a parallel RL circuit for the r and l values

texts:
I've a parallel RL circuit:

simulate this circuit – Schematic created using CircuitLab

And I know that (the RMS input-current) \$\overline{\text{I}}_{\space\text{in}}=2\$ A, (the RMS input-voltage) \$\overline{\text{V}}_{\space\text{in}}=200\$ V, the input frequency is \$50\$ Hz and \$\overline{\text{P}}_{\space\text{in}}=69.44\$ W now I need to find \$\text{R}\$ and \$\text{L}\$:

$$
\begin{cases}
\overline{\text{I}}_{\space\text{in}}=\frac{\overline{\text{V}}_{\space\text{in}}}{\left|\underline{\text{Z}}_{\space\text{in}}\right|}=\frac{\overline{\text{V}}_{\space\text{in}}}{\sqrt{\frac{R\omega L}{R^2+(\omega L)^2}}}\\
\\
P=\overline{\text{V}}_{\space\text{in}}\cdot\overline{\text{I}}_{\space\text{in}}\cdot\cos\left(\varphi_{\space\text{in}}\right)=\overline{\text{V}}_{\space\text{in}}\cdot\overline{\text{I}}_{\space\text{in}}\cdot\cos\left(\frac{\pi}{2}-\arctan\left(\frac{\omega L}{R}\right)\right)
\end{cases}\tag1
$$

Using the given values:

$$
\begin{cases}
2=\frac{200}{\sqrt{\frac{R\cdot2\pi\cdot50L}{R^2+(2\pi\cdot50L)^2}}}\\
\\
69.44=200\cdot2\cdot\cos\left(\frac{\pi}{2}-\arctan\left(\frac{2\pi\cdot50L}{R}\right)\right)
\end{cases}\tag2
$$

  But when I tried to solve the system I get imaginary numbers, what is my mistake?

EDIT:

I can write:

$$\cos\left(\frac{\pi}{2}-\arctan\left(\frac{2\pi\cdot50L}{R}\right)\right)=\frac{2\pi\cdot50L}{R}\cdot\frac{1}{\sqrt{1+\left(\frac{2\pi\cdot50L}{R}\right)^2}}\tag3$$

So, I get:

$$
\begin{cases}
2=\frac{200}{\sqrt{\frac{R\cdot2\pi\cdot50L}{R^2+(2\pi\cdot50L)^2}}}\\
\\
69.44=200\cdot2\cdot\frac{2\pi\cdot50L}{R}\cdot\frac{1}{\sqrt{1+\left(\frac{2\pi\cdot50L}{R}\right)^2}}
\end{cases}\tag4
$$

Now, for example we get:

$$2=\frac{200}{\sqrt{\frac{R\cdot2\pi\cdot50L}{R^2+(2\pi\cdot50L)^2}}}\space\Longleftrightarrow\space L=\frac{R\pm Ri\sqrt{3999999999999}}{200000000\pi}\tag5$$


texts:
I'm not an electrical engineer, but in reading the documentation of the system I work on, I'm coming across a lot of references to multiplexing. I'm wondering if my understanding of multiplexing is accurate and I've come up with an example. If someone could verify my understanding, I'd really appreciate it.

Assume I am working with a 10Hz, 16 bit message. If I have two quantities, A (12 bits) and B (6 bits), I immediately come across the problem of not having enough "space" (not sure the word) in the message to send A and B. But if I don't really need A and B at 10 Hz and say 2Hz will work, can I convert my 10Hz message into five 2Hz messages?

In other words, can I do this:

Group 1: A, 12 bits
Group 2: B, 6 bits
Group 3: Spare 1, n<=16 bits
Group 4: Spare 2, n<=16 bits
Group 5: Spare 3, n<=16 bits

Where each group is a 2 Hz message. I'm assuming that by splitting a 10 Hz message into five 2 Hz messages, I expand my "space" to 16 bits * 5 groups = 80 bits?

Follow-up Question:
Here's what confuses me. I'm looking at some work an (ex)-coworker did. They laid out a plan that basically goes like this:

Lets assume I have a bar that has five different super complicated lights on it. I have a two word message that has 16 bits per word that is capable of sending the message at up to 10 Hz.

My coworker dedicated 2 words (16 bits each) to one particular cause --sending three quantities, A (6 bits), B (8 bits), and C (8 bits), at 2 Hz. All five lights are controlled using this same message, so my coworker decided to multiplex these word and have five different mux groups for each word. So each light gets its command update every 0.2 seconds.

My question is this: how can all five commands fit in two 16 bit words?

I know the following:

(1 word/1 message) * (16 bits/1 word) * (1 message/0.1 sec) = 160 bits/second

So if I apply that same logic to my coworkers plan:

(5 words/2 message) * (16 bits/1 word) * (1 message/0.2 sec) = 200 bits/second

So in that case, I am exceeding my allowable bit rate (is this the right term?).

Could you point out the flaw in my logic? I'm pretty confident that he was correct, I think I'm just misunderstanding.

He ended up with A on one word with 10 spares, and B and C on another word with 0 spares.


texts:
In theory at least, SOIC is half the pin pitch of DIP and SSOP is half again. Thus SSOP is 0.1/4 = 0.025" or 0.635mm. Except I see many parts, from TI and Linear especially, which are SSOP (or TSSOP) with 0.65mm pin pitches. Which is slightly annoying.

Unfortunately, after say 18 pins in a row, the difference starts to add up so one has to be careful when adding footprints in Eagle.

The question is: was there ever really a standard for these parts or are manufacturers free really to do what they want? Or is this a metric vs imperial thing. There are 0.5mm TSSOP parts of course but they are more obvious.


texts: Using a single phase induction motor equivalent circuit in LTspice

texts:
I was planning to simulate a circuit which will control a single phase induction motor in LTspice where mains is 230VAC 50Hz. In my previous question, I failed to find an example:
Modelling a "single-phase permanent split-capacitor motor" in LTspice

I was looking for any single phase induction motor circuit at any torque just for simulation purposes. I could only find the following eq. circuit together with resistances and reactances:

Here is the link for this realistic circuit: http://www.globalspec.com/reference/63637/203279/section-6-single-phase-motors

I adjusted this circuit to use in LTspice simulation.
I guess all the reactances (X) in the above circuit are inductive; so to use in LTspice I need inductances.

Therefore since inductive X = 2 * pi* f *L; in my case I took L = X / (2 * 3.14 * 50). I took the slips as 0.005.

Here is after modification for LTspice :

My questions are:

1-) Is my modification reasonable and does it makes sense to use this in LTspice as a motor?

2-) There are two slips, I took both 0.005, for a fan motor is that reasonable in steady state?

note: I think a good motor simulation requires a lot of effort, but my aim is to represent the motor in LTspice in a very simple way.

edit:

link: http://eesiiest.weebly.com/uploads/2/6/9/2/26921317/478_eeselectric_machinery_6e.fitzgerald.pdf


texts:
A STM32F4 platform is used, which has 192kBytes SRAM, which is sufficient for me.

I am trying to build a look up table. The LUT will be used in calculation several times. And I want to put it in SRAM in the process of calculation, instead of FLASH, since reading SRAM is faster than reading FLASH for the core.

And I read this post mentioning putting the LUT in flash, which confuses me.. What should I do to burn the data into flash for the first load and the data will be kept in RAM afterwards for following calculations?

And if anyone knows CCM, is it a good idea to put the LUT in CCM during computation?


texts: Touch switch with conductive ink as thin as possible

texts:
First for all. Am not an electrical enginner, am just an amateur artisan, pretending make intetesting gadgets.

So the situation is this. I need to make a circuit in a sheet of paper for just turn on and turn off a very very little led light. The challenge: make this as thin as possible. Ideally with 0.5mm of thickness.

What I already made: I found a very interesting example in this link https://www.electroschematics.com/5996/touch-switch-circuits/

But the problem is, again, the thickness, only the  ic 555 has a 3.5 mm, for me its to much. In summary, is there another way to do this circuit but in a very very thin way?.


texts: Difference between wire and logic for this particular problem

texts:
I've worked this problem before in Verilog and no problem at all. Tried the same problem with SV and the problems started. The idea is to just show numbers on the first 3 7-segments based on switches. At first, it just didn't work (the 7 segments were "off"). The code I used there was:

module top(SW, CA, CB, CC, CD, CE, CF, CG, AN);

input [3:0] SW;
output CA, CB, CC, CD, CE, CF, CG;
output [7:0] AN;

logic [6:0] seg = {CG, CF, CE, CD, CC, CB, CA};

assign AN = 8'b00011111;

bcd_decoder_0 dec1(.out(seg), .in(SW));

endmodule

You may ignore the instantiation to bcd_decoder_0, because it has proven to be right. As I said, the above code didn't work. Changing the data type of seg to "wire" solved everything:

module top(SW, CA, CB, CC, CD, CE, CF, CG, AN);

input [3:0] SW;
output CA, CB, CC, CD, CE, CF, CG;
output [7:0] AN;

wire [6:0] seg = {CG, CF, CE, CD, CC, CB, CA};

assign AN = 8'b00011111;

bcd_decoder_0 dec1(.out(seg), .in(SW));

endmodule

Why that happened?

Note: I'm using NEXYS4DDR board from Xilinx, CA...CG represent the segments and AN represents which 7-seg is selected.


texts:
Electronics have a habit of breaking in my house. In the last 2 years or so, I had 3 desktops, 1 monitor, 4 cellphones going dead. They are not completely dead like they won't turn on. But in the case of cellphones, one of them end up showing only white screen at max brightness, and cannot be turned off. While another's capacitive touch screen stopped working. Just recently, my 8 months old Macbook Air is playing up and unable to charge every now and then. I haven't found a definite fix, but shutting it down and restarting, or unplugging the power cord a few times seem to do the trick... sometimes....

Being a student in Computer Systems Engineering, I am curious and suspect if it might be something to do with the nature of my house that's affecting these electronics. The first thing I thought of was surges or spike from the main AC power supply. As far as I understand, these, unless large enough, don't usually immediately kill electronics. Instead, they put strains on the system and results in significant shortening of life span. And shortening of life span is exactly what I have witnessed.

So I was wondering, are there relatively cheap and convinient ways for me to test my theory about spikes through the main? Or any other possible problem that might be taking place?

Obviously I can just be extremely unlucky, but I'd prefer to do some research and testing first, you know, engineer style.


texts:
I’ve got an 850mAh LiPo (https://www.sparkfun.com/products/13854)
hooked up to a charger circuit (https://www.sparkfun.com/products/10217) and 3V voltage regulator (https://www.sparkfun.com/products/526) to power a Gameboy Advance (AGB-001). I don’t quite understand why the battery drains so quickly when the unit is off (seems to last only a few days to a week maybe). I’m able to power on other natively LiPo-powered units like the Gameboy Advance SP or Gameboy Advance Micro just fine after months of being stored. Any thoughts?

Is there something about the voltage regulator that would cause this? I’ve seen other Gameboy battery packs for sale (e.g. https://www.retromodding.com/collections/gameboy-advance/products/gameboy-advance-rechargeable-battery-pack?variant=2565317361697) that have a switch to flip when storing for long periods of time, though I’m not sure if it’s to prevent drain.


texts: Is it safe to assume that all pins in a standard VGA cable are wired?

texts:
I am currently in the process of designing a custom arcade-style
joystick console for use with emulators on my PC.  My design separates
each joystick console from a single keyboard-encoder "hub" such that I
may add additional joysticks or upgrade the encoder circuit without
modifying existing joystick consoles.  The connection to the hub  may span
several feet, much like existing joysticks connect to their game
systems.

While designing, I became puzzled as to which cable and connectors to use for
connecting a console to the hub. I need at least 12 signal wires for
each console (joystick directions, buttons, and ground) and so I
thought of using a standard HD-15 VGA cable and terminals.  I am now
dubious that this will work in general as I've read that some VGA
cables don't wire all the pins.

Is the use of HD-15 cables suitable for my design and usage?  It is
definitely attractive as it is inexpensive and generally available.

What other cable and connector options are available to me and
suitable for this project?  Jumper cables are appealing as they
connect without soldering, but they don't appear to be available in
long lengths or as resistant to tangling as a VGA cable.


texts: Number of errors that can be detected with a single-bit even parity code word system?

texts:
How many errors can a transmission system which uses code words with 7 data bits and a single parity bit (Checking for Even parity) detect at the receiving end.

While I am aware of the fact that any odd number of errors can be detected with this kind of a system, what exactly would be the answer? Or is the answer just one?

Ps. I'm not sure if this is the right Stack site to post this question. Do let me know if it isn't.


texts:
I am designing a RFID rectifier. I am referring a IEEE paper for this purpose.
The paper has shown results for both 130nm and 350nm technologies. I have chosen 180nm technology.
So, I expected results in between the above technologies. To my surprise, the results are wierd - undesirable.

Let me explain you the stuff:

I have used the Widths as mentioned in the reference paper. The rectifier rectifies the input ac voltage from 350mV with an efficiency of 50%. So, I expected that I will be achieving atleast 20-30% of efficiency for 500mV to 700mV of input voltage. To my great surprise, I achieved efficiency less than 8%. I tried to use multi stage of rectifier; even then efficiency is less.

The current at the load is around 4uA. I varied the load from 10k to 100K. When load is 100k, current is 4uA. I varied the input voltage from 100mV to 1V (Peak values). The input current is increasing as the voltage is increasing. That is true. But I expected that the current at the input is same, when I go for 2-stage rectifier. I was shocked to see an increase in the ac current at the input end for 2-stage rectifier.

What should I do in order to increase the efficiency? DC load current is always around 4uA. I am able to see the voltage conversion efficiency. But I couldn't achieve power conversion efficiency. What should I do in order to improve PCE for the attached circuit?


texts:
I have a voltage source that has a square wave between 20V and 35V with 12.5khz frequency. Even i fully close the MOSFET, it is still conducting in rising and and falling edges of voltage source. How can i prevent this?

I added the LTspice schematic and analysis screenshots. The green lines are V(R1) and blue lines are V(source).


texts: How to check the source of reset in ATMEGA644p

texts:
I am trying to find the source of reset for ATMEGA644p, but I couldn't find the way to do it!

MCUCSR gives error in atmel studio as not declared and the datasheet also doesn't have it.


texts: Is it good idea to charge a battery from a starter-capacitor of an AC generator?

texts:
Some friends and I took a working electric motor out of an electric lawn mower.

We suspect it is a single-phase AC induction motor (correct me if I'm wrong) with a starter capacitor (pictures above). Our plan is to use this motor as a generator for a wind turbine. We tested the motor on mains voltage (230V 50 Hz) to prove its functionality. We also tested the motor twice as an generator. We used an air compressor to turn the cooling fan of the motor.

First test, we attached our multimeter to the original terminals of the motor. We got around 5-10V.

Second test, we attached our multimeter to the terminals of the starter-capacitor. That time we got pretty close to 30V. Obviously we want to get as much power as we can out of this thing, to "impress" our teachers (it's a school project).

Finally my question is: Is it a good idea to power something like a battery to these capacitor-terminals? (Of course we need to convert the AC to DC.)

I would also want to know if this generator can actually be used for a wind turbine?


texts: Basic nature of electric current/voltage

texts:
I'm curious about electronic/electric. I just want some visual, easy to understand explanation/depiction about basic nature of electric current/voltage, relations between them, why electrons make a light up, a batteries run gradually out and suchlike.

May someone list me some useful books/online site which address these topics? (Sorry if this question is so basic)

Thanks.

Updated:

In short, I want some books/website that I can learn to become an hand-dirty electronic technician other than a truly engineer. My background is in electrical engineering. Thanks in advance.


texts:
Whilst reading about differences between PNP and NPN transistors I came across the following circuit diagrams:
http://www.learningaboutelectronics.com/Articles/Difference-between-a-NPN-and-a-PNP-transistor

The uppermost circuit diagram, illustrating the function of the NPN transistor, shows the load positioned before the transistor.
The lowermost circuit diagram, illustrating the function of the PNP shows the load positioned after the transistor.

Would anybody be kind enough to advise if this is significant and a function of the type of transistor. My understanding would be that the behaviour of the load would remain the same, regardless of its position before or after the transistor.

Thanks


texts: Using battery charge port as normal power

texts:
So I'm designing a battery charger circuit. It has two connectors in, a main power source and then a powerbank can be connected through a USB C port. I understand that there are various IC's to handle this.
However, since my main power source is not a USB C port, I want to be able to use the USB C port to also power the circuit sometimes, using a standard USB C power source that you can plug into the wall. This is handy when testing the system in a controlled environment. But I'm unsure how to handle this, wont the charging IC sometimes try to "charge" the power outlet? Or is this automatically handled.
Thanks


texts: I am looking for some help on a system which I have here. There is a temperature probe in a tank which is monitoring the temp of a liquid and the controller output is switching a 3 phase contactor on and off when the temp of the liquid drops below the setpoint and then switches the contactor back off when the setpoint is reached again. The problem is now that over the weekend the contactor welded closed and kept heating the liquid which had to be dumped. There is an over temp alarm relay output on the controller which was not connected to the circuit therefore no failsafe. I need to configure this now so that the contactor coil switches on and off as normal through the relay output of the controller for when it drops below setpoint and then switch off when setpoint is reached. But i also must now get the over temp alarm into the circuit to switch the contactor off as well. I am a little confused as to how to go about this as in should i install a safety contactor so that if contacts weld shut no power will flow, should I put in a safety relay, or change the type of temp controller with different outputs instead of relay outputs. Or maybe a logic module of some sort? The temp controller in question is an Omron E5CSV


texts:
Given a 12-pole, 14-stator, 3-phase BLDC, how many possible positions are there? Since each stator could be aligned to each pole, there'd be a maximum of 14*12 = 168 positions. But how many of these are overlaps?

The reason I'm asking is that I'm trying to adapt the code here from a 9-stator, 12-pole BLDC to 14-stator, 12-pole.

EDIT: Mine's a 12-pole, 14-slot BLDC instead!


texts:
I have prepared the following PCB layout

I am a hobbyist and when I look at other - professional - boards, mine looks a little strange when considering the empty spaces to the right, and to a lesser extent to the bottom. But Eagle refuses to fill these spaces with GND conductor. I suppose there must be a setting in Eagle that controls fill polygon separation, but is it worth bothering at all?

I have learned (or at least I think I have) that in layouting for analog circuits, especially in the high frequency domain it is very important to have the ground area as close to the signal lines as possible in order to reduce capacitive coupling to environment noise. Preferably a separate dedicated ground plane.

But in my case it is just a pure digital circuit, and it's only up to 20 Mhz clock speed. The circuit works perfectly on my desk, but I have no idea as far as its EMC properties are concerned.

How would I go about the empty spaces? Should I try and separate the other lines until GND can fill the spaces, even if it means enlarging the board? Or should I leave them as they are?


texts: How to prevent a microcontroller to reboot due to Vcc fluctuations?

texts:
Case #1: I have a pump station with an autonomous 240V pump motor switched by a 240V pressure switch, feeding a pressure tank to a max. pressure. After said tank are four 24V solenoid valves (250mA inrush, 180mA holding), controlled by a 5V-fed relay board (Sainsmart). This relay board is connected to microcontroller (Arduino UNO) outputs via optocoppler.

The relays come ON|OFF in series. Once the last one switches OFF, the pump motor still runs due to the switch-OFF-pressure not reached yet. A few seconds later the pressure is up, the pump switches OFF -- and here comes the problem -- the microcontroller reboots (when the motor switches OFF).

There is a single phase 240V supply for all of it.
The solenoid valves get their power from a ring-core transformer 50VA.
The microcontroller has a 240V/5V switched plug-in power supply with 2A (<200mA required).

Case #2: Another scenario: the 240V/5V connected microcontroller controls a small relay (5A), which switches 240V (with snubber) for a bigger 25A DIN-mounted relay (contactor), which switches a 3kW resistive heating element for a hot water system. On occasion, the microcontroller reboots when it switches on the load.

I see the same problem in both cases. But what could be the problem/solution?

100uF with 0.1uF in parallel to 5V Vcc/GND?

Case #1: the trials...
1. use a 4k7 and parallel 100nF from +5V Vcc to RESET. No change.
2. use a 1,000uF capacitor parallel to +5V Vcc and GND. No change.

Case #1: the solution...
3. add a snubber (104 in series with 100R) parallel to the relay contacts.
No more rebooting problems! :)

Thanks for all the input; it triggered a lot of research and validation, resulting in some learning... more so to create more robust circuits, when it comes to inputs into uC devices.


texts:
How to protect an arduino from dust and moisture ?
I have already made an RPM datalogger using arduino and placed it in industry.I wanted to protect arduino from dust and moisture.I also want to know the life of arduino.


texts: LVDS (from PTN3460) driven display shows fringed lines

texts:
I am developing a board which converts DisplayPort to LVDS. The LVDS is put through a PCIe switch and then fed to an APIX transmitter, which connects to the display.

There's a second video path going to this PCIe switch. If this path is active, I get a perfect image in the display.

https://www.youtube.com/watch?v=b9cWaxLYY4M

That video shows what I just wrote, starting with a nice image it gets really bad when I change to the DP source.

I think I have two seperate problems here. One is responsible for the "fringing" or jittering lines, and the other is responsible for the DP image being a few centimeters to the left and cut off. My main concern is the jitter, I think the position of the image can be adjusted by playing with parameters like front and back porch.

Here's a detailed view of my issue:

https://www.youtube.com/watch?v=O6tb6PG9xOs

The position of a view pixels seem to "jump around". The lines are ok and at their correct positions, but sometimes a line is longer than it's supposed to be and fringes appear to the right of the image.

Where shoud I start debugging this problem?

The PTN3460 is set to single LVDS, single DP lane, the resolution is 1280x480 at 60Hz. I also used these parameters:

pixel clock 40500Hz
hor active 1280
ver active 480
hsync width 15
vsync width 1
hblank width 86
vblank width 14
hpol neg
vpol neg
htotal 1366
vtotal 494

I also have these:

hblank start 1350
vblank start 480

But I am not sure what to do with them, because I am using the "EDID Generator" from analog devices to generate an EDID file. That EDID Generator is asking for:

I am not sure what to do with hor/ver sync offset and hor/ver border, and the unused hor/ver blank parameters, though.

I got the values from the machine that creates the working video output, shown in my first video, the one with the huge tiles.

There's another (commercial) board available, using the exact same EDID I get a clean image. The major difference between their board and mine is: They use HDMI, I use DP.

Where would I start debugging this thing? I have an oscilloscope with 2GS/s and 200MHz max, and a multimeter available.


texts: What's the effect of S21 in two port antenna system?

texts:
When designing two port antenna, S11 is quite well with other antenna performance like gain, efficiency, etc. However, S21 is around between -6 / -10 dB.
If we consider that a commercial coupler will be used, what would be the effect of this S21?
If I already got the good antenna performance (S11,gain, eff. etc), does S21 still become important?
Thanks
KR


texts: Using Arduino PWM to drive an incandescent lamp

texts:
I'm trying to drive an incandescent lamp using Arduino Leonardo PWM, the incandescent lamp has the following electrical specifications:
peak voltage=1.4 V (max)
peak current= 1.14 A (max)
peak power = 1.6 W
If it is not possible, could I use 555 IC instead of Arduino?
Thank you in advance


texts: Best way to use multiple decoders for an LED matrix

texts:
I'm designing a 16 x 32 RGB LED Matrix and its controller / driver board.
So I've designed a couple of solution approaches and I'm wondering if there is a better way to drive multiple 4 to 16 line decoders ( I am using the CD4514B ) than the solution I'll show in the image below.

Some background information:

Simply I want to use two of the 4-16 decoders to end up with 32 channels so I can select/enable ONE row|column of the matrix at a time.

The other row|column ( the 16 pin side of the matrix in this solution ) is selected/activeted by two 8bit shift registers ( times three since RGB ).

At this point I'm not sure if I should control the 16pin side by 2x shift registers and the 32pin side by 2x 16bit decoders OR control the 16pin side by 1x 16bit decoder and the 32pin side by 4x 8bit shift registers.

I am also not shure if I should/can split the matrix into 8 individual 8x8 matrixes, and why I should do that...

Since I dont even know which AVR I'll be using as the main unit at this point, I don't know how many IO pins I can use. Even if I want to keep the size and costs as down as possible, I dont want to run into some timing / speed problems. And that is the point - I dont know which design suits the best, because I will need many shift registers in a tree-like-structure when I want to use a small AVR like the ATtiny45 ( 5 IO pins ).

So If you have some ideas / experiences about this, please tell me.

But to come back to the original question, here is my thought about the dual 4-16 decoders:

What do you think about it ? Is this the common way to do this ?

For sure, for chaining more than 2 decoders, I could simply use another ( e.g. 3 to 8 bit ) decoder, just to control the inhibits, but for this one I'm dealing with only two.

Thank you for your help.


texts:
I am being driven up the wall with designing an 8-bit VGA DAC for an embedded application.

Everywhere I've researched highlights the necessity for "impedance matching" the 75 ohm termination resistance of VGA monitors, yet I've seen myriad solutions such as this:

this:

this:

and most commonly this:

Yet none of these as far as I can tell come anywhere close to impedance matching.

This thread from this very website lead me to implement the circuit depicted here:

Yet this circuit caps my outputs at .63 volts as opposed to the standard's .7 volts, resulting in a noticeable darkness in colors.

So, at this point, I'm at a complete loss as to how to get a 0V-.7V 3-bit weighted or R2R DAC which outputs accurate values given a 75 ohm termination resistance. Because apparently, with the tons of other solutions out there, no one else has a single answer either.


texts: How does a bridge rectifier work exactly?

texts:
If this question was posted before, please let me know.  I searched for "how does a bridge rectifier work" and did not find an answer.

The part that I especially find confusing is when I have the four diodes in such a way and how each reacts to the incoming AC.


texts: Android ATtiny arbitrary data communication over USB

texts:
I have an ATtiny13a running code at 9.6 MHz (internal oscillator) for single pin Tx Rx half-duplex serial port at 115200 baud rate using a lib which I found online

Using FTDI 232RL or BT HC-06 in between I am able to send & receive arbitrary data between the MCU circuit and Putty/Android.

What would be the cheapest and smallest (in terms of PCB size and ATTiny memory) way to achieve the same arbitrary data communication to an Android device (non-rooted) instead of BT.

Also is there a way to achieve it keeping the MCU circuit in accessory mode for Android and NOT using Android's host mode since the MCU circuit will be powered externally and not from Android. The MCU's power source will also be delivering power to Android on the USB's Power buses.

How can I achieve arbitrary data communication between ATTiny in accessory mode and Android over USB?

Will VUSB work in this case? or do I have to buy a converter chip (CHG340?) but will that chip work in accessory mode? Also will there be any changes to support USB Type C port?

Thanks


texts: Why can a coin cell power an LED without a resistor?

texts:
I have always been told that LEDs need a resistor in series when powered from a battery.

If this is true, how is it possible to power an LED from a coin cell battery without a resistor? I have tried this, and it works without burning out the LED.


texts: Connect 3 Lithium Polymer battery with different capacity in parallel

texts:
I am working on an IoT product with has a total current requirement of 1.3 A at the peak. Due to space constraint, we decided to select Li-Po battery with capacities one with 600 mAh other two with 350 mAh each and the voltage rating is the same 3.7V. to get total 1300 mAh we are connecting them parallel.

Now we are looking for a charging IC which will support this parallel configuration with different capacities and same voltage rating Li-Po batteries. How can we solve it?


texts: Is a power distribution board just a board that connects all grounds and all positives?

texts:
I'm thinking of designing a PCB for a quadcopter but want to directly integrate the power distribution board (power going to the ESCs that power the rotors). I would just like to confirm that it's as simple as connecting all the grounds together and then connecting all the positive connectors (as per this link)? Or is there more to it?

In addition, I do need some kind of voltage regulator so that the battery can also power the Arduino running the quadcopter - can I simply use an LM7805 voltage regulator given my battery is 12V?


texts: How can I measure the supply voltage of batteris without a multimeter?

texts:
My system consists of two XBee S1s and a Raspberry Pi. I've attached a TMP36 sensor and a LDR to the first XBee S1 and transmit those infromations to the second XBee S1 via the ZigBee protocol. The second Xbee S1 is connected via USB adapter to the Raspberry Pi. My first XBee S1 is powered by batteris at 5V.

As the voltage given by the batteries decreases over time, I would like to have an indeication of the voltage supplied by the batteris in order to know when I should change them. Can you tell me how can I do that? My idea is to make a gauge with 4 LEDs attached to the Raspberry Pi. The problem I am facing is that I do not know how can I send the supply voltage via the Xbees(as the XBee 1 itself is powered by that battery).

PS: I don't want to use a multimeter every time I am  wondering how much voltage is provided by the batteries.


texts:
What is the disadvantage of oversampling a signal?

For example, if I sample a signal at twice the Nyquist sampling rate, what will the disadvantages?


texts: Powering a microcontroller circuit using a differential voltage instead of an absolute voltage

texts:
So this is a more theoretical question. Imagine I have 2 perfect power supplies that I can set to whatever voltage I feel like (10 000 VDC for example).

Now I know that when it comes to voltage it's the potential difference that you actually use (e.g 10 V on GND and 15 V on VCC gives the chip 5 V).

As an example, imagine I have a simple microcontroller circuit with the correct track spacing and width. If I put 10 000 V on the VCC pin and 9995 V on the GND pin of the circuit, would it still power up? Would there be some other adverse effects if I was to implement this practically or would it be no different to using 5 V and 0 VDC.
Is it the same using negative voltages (-9995 V on VCC and -10 000 V on GND)?

My main question is, could you power a circuit using whatever voltage you wanted as long as the difference between the voltages is the same as the component ratings (e.g 5 V)? I know in theory the maths says "Yes" but practically would it be any different?

I want to reiterate, I am not actually planning to power a circuit with 10 000 V so no "You're going to die using that voltage" please.


texts: Understanding this LPF in opamp feedback loop

texts:
I'm using a basic opamp driven mosfet to implement a precision low current sink for an LED:

This seems to work just fine within the range that I want it (10mA or so). I've seen other circuits that put an lpf in the feedback loop (R3 was 1K in the one I saw):

I'm trying to understand how that works. With the values of 100n and 10k, the -3dB point is 160Hz. What I don't understand is why the capacitor is connected to the opamp output instead of to ground. Wouldn't that divert noise above 160Hz back into the output? Of course, there'd be a phase shift as well but I cannot see why you wouldn't connect the capacitor to ground.

I'm guessing this is a really basic opamp circuit in a slightly different form but I'm not understanding what that form takes. I may have it backwards as high frequencies at the output of the opamp will "short" back to the inverting input and reduce the opamps output.


texts: Cabling simple sensors 5-20 ft from a uC - tips and gotchas; UTP vs STP cables

texts:
The situation: using a simple microcontroller (eg: 5V Arduino Pro Micro) which needs to read a few sensors located about 5 to 20 feet away via cables.  (This is a garage/storage area controller).

The sensors: switches (pushbutton or magnetic reed), resistor (Light Dependent Resistor for reading light levels), and PIR motion detectors.  Yeah, I could use a wireless network of microcontrollers and just run AC to a power supply for each; or a wired network.  But I wanted simple and cheap and quick to build.

I'd like a reality check on my thoughts on how to do this:

1) For reading a remote switch - two wire cable to the switch; at the uC end one wire to ground and the other to an input pin and a pullup resistor to Vcc.  Use a lower impedance external pullup rather than the internal pullup, for more noise resistance.

2) For reading a remote LDR - basically the same thing, but using an analog input pin and treating the LDR + pullup as a voltage divider.

3) For reading a remote PIR - three wires: VCC, Ground, and the logic level detection signal back from the PIR and to an input digital pin on the uC.  These PIR sensors generally use very little current so voltage drop on the power line is not much concern.

Cables: in the simplest case, just use some 4 conductor phone cable I have a spool of.  However I could cut up a Cat 5 ethernet cable (UTP) - using twisted pairs.  In the case of the PIR, use two pairs for power/ground and for signal/ground.  Would that help?

Or I could get some STP (shielded twisted pair), and wire it the same, except also ground the shield on the uC end only.  (Maybe to earth ground?)  Would that help by shielding the conductors from RF and 60 Hz, or just add capacitance and make the situation worse?

Also - I'm a little concerned about the signal wire back from a remote PIR - as described it might be fairly high impedance and easily pick up hum.  I wonder if a small value in-line resistor would help reduce reflections, or if larger value resistors to ground &/or power would help to disinvite gremlins.

Maybe some large and small caps at the power inputs of the PIR?

Again, I'm talking about 5 - 20 feet, and very low speeds.  So it's beyond normal chip to chip or chip to sensor distances, but not getting into mandatory RS-485.  In this case I'm thinking it can be done with the right choice of cable, and maybe a few small passives - no need for multiple uCs with multiple power supplies and communication transceivers and a network protocol, just some wire and judicious resistors.

Yes?


texts: Question about a CMOS operational amplifier

texts:
I'm studying CMOS op-amps. At the very beginning of the chapter, the author of my book says:

"obtaining low output impedance can be problematic. Nevertheless, the typical use that we make of op-amps in integrated systems does not lead to a strict request for low output impedance. Even better, in some cases the output impedance may not be
a problem at all."

To prove it, he proposes the following example:

He finds the following expressions:

He then says:

"Since 1/gm is much smaller than r0, the time behaviour of the output voltage is mainly controlled by the transconductance gain and is almost independent of the output resistance. [...] When the feedback network comprises only capacitors (and switches) the output resistance is not relevant. We can use a special class of operational amplifiers where the output resistance can be very high and, possibly, used to enhance the voltage gain. This class of operational amplifiers is called OTA (operational transconductance amplifier)."

Question 1: why does the author model the op-amp with a transconductance generator gm*vi having in parallel the output resistance r0? The model of an op-amp should be the following:

Question 2: I'm able to find expressions 5.3 and 5.4: the charge on C1 (i.e. Q1=C1*vin) is shared with the series connection C-C0. But why does the charge on C1 distribute only on the series connection C-C0? Actually this charge has also two paths toward ground through which it can flow: r0 and the voltage-controlled current source.

Question 3: I'm not able to find expressions 5.5, 5.6 and 5.7. Can you give me some hints?

Question 4: the author says that it is an OTA, whose working principle is based on a very large value of the output resistor. But why does he talk about OTA if the chapter is dedicated to op-amps?

Thank you


texts:
I have been thinking about the permanence of information lately and I was wondering at what rate a bit on a consumer spinning disk hard drive is corrupted and what are some factors that speed up or slow down this rate? I am astonished that programs written to memory today may slowly decay in time due to decaying memory! Will programmers in fifty years have to spend time repairing or recreating ancient underlying libs?

edit:Thank you @clabacchio for pointing me to error correction algorithms, these usually  treat the problem I am anticipating here.


texts: What would happen to the turn-on transient if I add a capacitor in parallel to a transformer?

texts:
I have a welder with a big air gapped transformer. Input specs: 220V, 3200 W active, 25 A total (cos Phi 0.56). Output specs: at full load 110 A welding current. I haven't checked whether output is DC pulsed (simple rectification) or is AC, but the electrode connector is marked as "ground" and the clip ("pinza") as such, so I guess it's rectified. The welder is rated for "intermittent" use for 3.2 mm electrodes, and continuous for 2.5 mm electrodes.

When I switch it on, if the current is set to more than 50% of full scale, the overload switch in the garage trips.

Also, at full power the total input current (25 A) poses a strain on the standard plug that is provided (16 A power plug, I wonder... '70s safety I guess).

I could add a capacitor of about 150-200 uF to improve the average power factor during use and reduce strain on the plug and wires, but what would happen to the inrush current?

Since in the transient no magnetic field is present and the transformer is like a plain wire, I would expect no change in the inrush current, therefore requiring a soft-start circuit.


texts: 'FEC limit BER' in communication systems

texts:
What is the maximum BER that a FEC can correct?

In one of the IEEE papers the value mentioned was 10^(-3).
My question is when FEC can correct BER upto 10^(-3) then why do many communication systems specify BER requirements to be 10^(-12) to 10^(-9)?


texts: Where can I find easy to understand instructions for real world applicable inkjet printed electronics

texts:
To explain what I'm trying to do a bit more, here is an overview of my ideas in this case.

As far as I understand so far, it's technically possible to create complete PCBs including chips, memory and screens with inkjet and or 3d printing and the right inks. Graphene seems to be a non toxic wonder material for this.

I am not an electrical engineer or a skilled programmer so my understanding of the limitations here is very basic.

The most promising examples I have found are these here:

print a working paper computer
https://www.newscientist.com/article/mg22029374-500-print-a-working-paper-computer-on-an-80-inkjet/

printed 8-bit microprocessor:
https://electronics360.globalspec.com/article/4824/8-bit-microprocessor-opens-path-to-organic-iot

Printed paper memory
https://www.nanowerk.com/spotlight/spotid=36722.php

Printed tft Screens
https://www.youtube.com/watch?v=2qg5BXH1mPs

I have been trying in my spare time to find simple DIY instructions so that I can start experimenting with printing usable electronics at myself.

By this I mean complete circuits including the microprocessing units.
I love sites like Instructables for DIY things like this, but the best example I found there was an inkjet printed circuit with no processing capabilities. http://www.instructables.com/id/Print-Conductive-Circuits-With-An-Inkjet-Printer/

I know companies like PragmatIC are already quite advanced in this department. They make RFID tags, printed displays NFC, powered devices.

The instructions I have found on this topic are all very technical research papers that are mostly beyond my understanding.

I need the "How to make an inkjet printed computer - For dummies" Version.

Any links pointing to simple DIY tutorials  would be greatly appreciated. With all the amazing posibillities in this field I imagine there must be a large community like this somewhere that I have not been able to find yet.

If further clarification is wanted please let me know and I will try to explain what I'm looking for better.

Thank you for taking the time to read this.
I hope this is not too off topic for the site

Thanks to all the answers I am now realizing that none of these examples actually have inkjet printed processors.

Thank you all for pointing that out. I see my question should be about how to print transistors/processors.

Printed transistors apparently are possible, but as I see now the company in that paper seem to be the only ones claiming they have printed a processor and I'm not finding any further evidence yet


texts: How should I connect the RESET pin in a microcontroller (AT8051), and why in that particular way?


texts: Variable output LM317 power supply circuit - potentiometer burning

texts:
I have just finished making my first power supply. But when I tried to use it the potentiometer was burned. I tried different fixed resistors and all the resistors below 10k ohm gets burned.

What seems to be the problem?


texts:
Im using 123d circuits by Autodesk and I am trying to make a NAND logic gate.

When i simulate my circuit (one in picture) it does not work and the LED does not turn on. I am using 2 NPN transistors, 2 switches and 3 1k resistors. The battery is 9v. Can someone help me find whats wrong with it?


texts: Is it correct to use "wattage" and "amperage" instead of "power" and "current"?

texts:
Is it legitimate to call the name of an electrical quantity with the name of the unit of that quantity by adding the -age suffix to it?

Examples:

1. Power                --> Wattage  (Rarely used.)
2. Current              --> Amperage (Rarely used.)
3. Potential Difference --> Voltage  (Frequently used.)
4. Resistance           --> Ohmage   (I made up this one.)


texts: Television antenna comparison for signal reception

texts:
I bought two antennas for over-the-air TV reception.  They are the "Mohu Sky 60" and the "Channelmaster CM2020."  I was wondering which is likely to get the strongest signal before amplification when the transmitters are about 35 miles away.  I have the Mohu mounted at the peak of my roof, but some channels are still dropping out or pixelating severely - even with amplification.  I have excellent signal strength but very poor signal quality.  I'm wondering whether I will get a better signal if I mount the ChannelMaster in its place.

I searched StackExchange sites and it looks like this is the most appropriate community where I could ask this question.


texts: Speaker protection using only zener diodes?

texts:
It is crucial to match amplifiers to speakers correctly and use them with care.  But in some cases you want extra protection from blowing up the speaker.  I have thought of a ridiculously simple idea - to use zener diodes parallel to the speaker.

Zener diodes let through current only after certain voltage point (for example 5v) and by doing so they keep the voltage stable at that point. Zener diodes are mostly used as voltage regulators.

Not sure if it is wise to do so and how it will clip the sound when the diodes start letting through current of overvoltage but as I see it - it might clip the sound badly but it will still protect the speaker from too much voltage going in. I have found few circuits using this technique but descriptions are really lacking and I am not sure what to expect.

Sure, there are better options than using zener diodes as speaker protection circuit but for the sake of simplicity I am very interested if this would work as intented - protect speakers from over-voltage and power peaks.

My (simple) circuit design:

*Light diode acts as a clip indicator

simulate this circuit – Schematic created using CircuitLab

Similar circuit I have found online though it does not use any resistor in between them basically creating a 2ohm short for voltages over (in example) 5v.  Could anyone comment how would amplifier handle such circuit design?


texts: Switching a current source through a MUX

texts:
I have a current source of square pulses (0-20 uA) generated by a NI 9265 device. I  am trying to build a fast switching circuit using TI CD4051 multiplexer to switch the current signal between different channels to apply it to different electrode pairs.
The problem I am having is getting current on all channels even when all channels are OFF. Mux however is doing fine with a voltage signal.
Any suggestion would be highly appreciated.


texts: How to determine the saturation level when an opamp schmitt trigger starts worknig?

texts:
The Opamp inverting schmitt trigger is constructed as shown.

The output signal is

So I ask why is the output at the start of operation saturated to positive?

Also, if the input voltage is moved from the negative to positive terminal the starting output will saturate to negative. Why?

Is there a rule to follow? If so, what causes this rule?

What will happen if R1 is replaced with a capacitor, as in a monostable multivibrator?
What will be its starting saturation level that will charge the capacitor. What will be the UTP and LTP then?


texts: What are the reasons two DC motors with same specifications and running with same power supply run at different speeds?

texts:
I am using two DC motors in my circuit.
They are running on same single supply and also using same motor driver but one of them is running slower than the other one.
There is 1.54 volt difference between the output of both motor drivers to the motors.
If I swap motors then I can clearly see that speed of the motors change, the slower one  earlier now runs faster and vice-versa.


texts: What is the purpose of all these resistors and capacitors in this power supply?

texts:
This is the schematic diagram of pa-12 family laptop adapter. I think it is based on flyback topolgy but i have a problem understanding many things in it.
Actually, in many circuits in general electronics i find many things like that and I can't figure out why these components are here? i understand the main concept of the circuit but the details are  big mysteries for me. Anyways, I have pointed out to some of them in this circuit.

1- Are these resistors for filtering ? there are 2x1M ohm series resistors, why don't they just put one 2M ohm resistor?

2- The same,  there are 2x750k ohm series resistors, why don't they just use one 1.5M ohm resistor? (Is that about standard values?)

3- What is that?

4- the same as question 1 and 2.

5- why don't they just use 1 equivalent capacitor ? .

6- What is that?

7- Is this a feedback network ? why don't they just use Ic ?

8- What is the purpose of this cap ?

9- What is the purpose of this resistor ?


texts: ESP8266 reduce power consumption caused by extra ICs/components on board during deep sleep

texts:
I need to reduce the power consumed by a circuit based on ESP8266 and extra circuitry (I2C sensors, light resistor based sensor, etc.). By now when I set ESP8266 in deep sleep I still have a relevant power consumption caused by extra components. Not all ICs have a 'deep sleep' mode that can be set to reduce power, so I tried to disconnect VCC line that power all extra components on the breadboard and the current drop enough to allow running the entire circuit by battery.
So my idea is to manage the sensors VCC line with a mosfet driven by the ESP8266, something like:

on ESP8266 power up (Arduino setup() method), as first thing I switch ON the mosfet to power all sensors
small pause to allow all ICs to init and stabilize
perform all operation (read sensor, calculation, etc.)
turn mosfet OFF
turn ESP8266 to deepsleep

So I would ask:

is a feasible way or can led to any kind of issue?
if I use an N-channel mosfet the result is a low-side-switch, that leave GND floating. This seems bad to me, correct?
if I use a high-side-switch (P-channel mosfet) is a pull-up resistor enough to assure mosfet is full-close when micro going to deep sleep?

The entire circuit VCC is 3.3v


texts:
I am starting a project and I need a colour screen preferably clear to shuffle through images (think of it as the digital photo frames). However, I need something bigger than the usual screens, maybe 10".

After looking around for a while I didn't find anything fit into my project. What are the popular good LCDs which don't draw a lot of power and are fairly easy to interface?

Should I even go after TFT? Power is really important as my source is limited.


texts: I am trying to control the torque of a 24V-DC fan (datasheet) using an arduino. A control system with feedback must be setup to continuously check the torque of the motor and correct it, if the value isn't desired. Currently, I have an ACS-712 set up in series with the fan to measure the current through the fan because I know torque and current are proportional. The reading from the current sensor will go into the arduino as an input. This is where I am stuck now. Once the arduino gets the current reading, what do I need to be able to actually change the torque of the fan. I have read that I may need an H-bridge to do this, or some kind of motor driver. What do i need to accomplish this. Any help is greatly appreciated!


texts: What happens to the capacitance of a system if capacitors are charged in parallel and then put into a series circiut

texts: If you have 2 capacitors 2V, 2F each. When you charge them in parallel, the system will have 2V and 4F when you attach a load to it. If you take the charged capacitors and then put them in series, does the system just change to 4V, 1F? What happened to the other 3F? Why does this happen?


texts: Solving 5 variables Karnaugh map - grouping with hazard

texts:
Welcome, according to topic Solving 5 variables Karnaugh map - grouping I would like to ask you if for this exercise, should I create anti-hazard group? Is it good?

The solver http://www.32x8.com/ which was mentioned does not show anti-hazard groups, so I am not sure if my thinking is good.


texts: Measuring Power across a dummy load - use voltage or current?

texts:
I have a high power 8Ω resistor dummy load (approximating a speaker) which is being driven from the output of an audio amplifier.

I want to measure the power consumption and display the results on an LCD screen using an Arduino. The Arduino will handle any unit conversion, RMS converting, etc (as well as a bunch of other, unrelated functions).

I have two options at my disposal:

A. Measure the voltage. I can convert the AC voltage across the dummy load by using a bridge rectifier, a small filter/smoothing cap and a 10:1 voltage divider to allow the Arduino to safely read the voltage as DC at one of its analog input pins.

From there, it's a case of reading the voltage, converting to RMS equivalent and using the formula P = V²/R = V²/8Ω.

B. Measure the current. Using a current sensing chip - such as the simple ACS712 module here - I can read the current being drawn and feed the output voltage from the chip into an Arduino analog input pin. In this case, zero amps would read 2.5V at the Arduino, and 20 amps would read 5V, with a sensitivity of 100mV per amp. With the current known, I'd use P = I²xR = I²x8Ω.

...

Questions:

Apart from cost/complexity/part count, What are the advantages/disadvantages of each method, particularly as it pertains to accuracy and tolerance? The maximum power I'd need to read is around 300W.
The 10-bit ADC AVRs (Arduino Uno, etc.) have a scale of 0-1023 on their analog input pins. If I jumped up to a 12-bit ADC (giving me a range of 0-4095) would that in effective immediately provide me greater accuracy, as the input voltage would now have significantly finer resolution?


texts: I can not receive radio waves using LM386?

texts:
I've made two different circuits to receive RF using LM386 but they doesn't work. I've changed the values of C2 and L1 to change the frequency. I've also changed the gain but nothing happens.

The problem is that I hear a sound of noise or buzz from the speaker.
When I touch Pin 3 (The input) or the Antenna, The sound become higher but anyway no radio station is received.

I've made a radio transmitter using a transistor before so, I turned it on. The receiver circuit received the song Which is the input of the transmitter. It receives no matter the values of the C2 and L1 of the Tank circuit so, I removed the tank circuit and connected the antenna directly to pin 3 and It also works receive the song.

Why it doesn't receive any radio station although it receive the signals that are transmitted by the transmitter circuit that I've made ?

What can I do to receive radio stations ?
   ( I live in area Where I can receive good radio stations AM and FM from my cell phone and Radio device )

here is the datasheet of the IC : http://www.ti.com/lit/ds/symlink/lm386.pdf


texts:
I am trying to build a variable power supply using a transformer with a 12V 0 12V - 5 ampere output. I am using a BR1010 rectifier. I have connected the 2 - 12V wires from the transformer to the AC input of rectifier. At the output of the rectifier I have connected 2 - 25V 2200uF capacitors in series. The output I am getting through the capacitor is 40V. How is this voltage increasing?
I want to pass this into a XL4015 step down module so that I can control the voltage in a more proper manner but the input range for this module seems to be maximum 36V.
What can be done in this case? Am I doing something wrong? Any help is appreciated. I am posting few pics of my circuit.
Yellow wire is 12V-12V output from the  transformer that is connected to input of the BR1010. The red and black wires are connected to the capacitor in series (2*25V). PS: Ignore the red wire to the XL4015 module.


texts: I have studied that there is a transformer which steps down the ac voltage after then bridge rectifier to convert into ac to dc and then given to filter, this is what I have learnt in books, but when I open a mobile charger I couldn't figure it out how it actually works?


texts: Has anyone used partsim and if they have, where is the potentiometer?

texts: Thanks you all for reading. Lately I have been trying to use www.partsim.com to model a vintage synthesizer in hopes of building a real one with real hardware. However it's really expensive to do so and I don't know anything about electronics so I don't want to waste my time and energy if I'm not good enough to do the project. Was wondering if anyone has used it and if they know if there is a potentiometer object and a 2 pole - 3 way switch object.


texts: Powering up second LM386N results in screaming squeal

texts: So I'm definitely a newcomer in the audio electronics realm but I've been really digging into circuits and experimenting with sounds. I've been focusing alot of time working through examples that use pairs of LM386N ICs for a distorted audio signal. In the circuit I've posted here I'm getting a loud squeal whenever I powerup the second LM386 in the chain. Could someone tell me what I have wrong that's causing this to happen and what I need to do to fix it? Thank you!


texts:
Can anyone show me a simple circuit to shift a 0V/5V square wave (low freq, under 10Hz) to a square wave -10V (when was 0) to +10V (when was +5V).
Can it be done with some transistor or do I need an opamp?


texts: Can motor run capacitors be used in high frequency applications?

texts:
What, if any, problems would arise when using motor run capacitors in circuits operating in higher frequency ranges?   Such as 2000 to 10,000 Hz or 10 to 100KHz

As they are only intended to run in 60Hz applications,  I'm wondering if internal resistance would become noticeable and cause excessive heating or if some other potential issue will arise.  What is the range of internal inductance on a motor run capacitor?  That would surely be more noticeable at higher frequencies.

I'm considering such capacitors for my application because of their large capacitance and modest voltages at a low price point.


texts: My optocoupler doesn't give more than 1.86V

texts:
I didn’t have anything else so I am trying to use a 4N35 optocoupler to power a 5V relay with an ESP8266 which only gives 3.3V maximum.

When I connect the circuit as shown in the image the output gives a maximum voltage of 1.86V. I have tried with a 5V and a 9V supply but the value stays the same.

I don't have any idea what is going on since is the first time I used a optocoupler with 6 pins.

I changed the image to a better one of the full circuit:


texts:
I want to verify that the quadrature current through a permanent magnet synchronous motor (PMSM) is actually the same amount as I commanded the field-oriented control (FOC) motor controller to push it through.

I have only one current clamp so I can only measure one phase at a time. Is the actual motor current just 3 times the RMS current through one phase?


texts: Why do we need a chain of resistors to increase the voltage?

texts: I did a workshop on SMT today and we made this board attached. However, what I don’t understand completely is the logic: why do we need 3 resistors to increase the voltage (on the boost part)? What do they do exactly?


texts:
I want to sum/mix 2 PWM signals in order to reach a better resolution on a DAC (see here or here).

I need help to understand the limitations of a simple resistors network to sum my two signals as described in the previous links. Indeed, I succesfully implemented this to sum two 3-bits PWM running at 10kHz as a test and I am now wondering what can be the advantages of summing those signals by using an op amp or by using "complex" circuits like the one described in the second part of the first link.

I understand that with the passive resistor summing, I have to be sure my two PWM signals have the same impedance but it should be the case as they come from the same MCU. I also understand that this method will not give the best results in terms of distorsion but as long as I am not using this to carry audio signals or other sensible signals, it should be okay, right ?

Briefly, I'd like to know your opinion on using passive resistors suming to mix let's say two 8-bits PWM signals at around 10 kHz in order to emulate a 16-bits PWM signal and what can be the pros and cons of using another "sophisticated" method. The resulting signal after filtering has low frequency (<1 kHz) but requires good SNR.


texts: Transistor for UnderVoltage Lockout (UVLO)

texts:
this is a circuit in LM2596 datasheet which suggests using zener+bjt combo to protect against UnderVoltage in regulator input :

it turns the regulator off using its ON/OFF pin.
I have many D882, 2SC3650 and BCP56T1 transistors in hand (all NPN).
Can I replace the 2N3904 with one of these NPNs I have?
if not, what parameters should I look for in transistors to replace this 2N3904?


texts: How do I know if my hall-effect sensor is working correctly?

texts:
On pg. 18 Figure 5 of this data sheet you will see a pulse train required to program the sensitivity of the A1362 Hall-Effect sensor.

I am using the following circuit:

Using Figure 5 from the data sheet, I simply power on the Hall-Effect sensor by supplying the 5V VCC.  Switches SW8,9,and 10 start out being in open state.  Here are my steps:

Close SW8     // high pulse
Open SW8
Close SW9     // mid pulse
Open SW9
Close SW8     // high pulse
Open SW8
Close SW9     // stream of mid pulses, each time incrementing sensitivity counter by 1
Open SW9

repeat steps 7,8 0 - 255 times as necessary to set the sensitivity of hall-effect sensor.

When I bring the north / south pole sides of a magnet close to the hall-effect sensor, the voltage readings I get at the VOUT pin are almost identical. But if the sensitivity of the hall-effect sensor has changed I should get different voltage readings.  This means I am not setting the sensitivity correctly.  What am I missing?

From previous posts, others have said to watch out for my current readings too. So here is some more information:

At VpH the multimeter reads ~ 200mA
At VpM the multimeter reads ~ 100mA
At VpL the multimeter reads ~ 3.5mA


texts: I made a simple project, a "Hello World" test. The LED's light up, but when I turn the power off for the PIC18 they still stay on for a few seconds. I want to turn off the power to the PIC18 with no delay; is that possible?


texts: How to re-solder fine broken flex cable connection to pcb

texts:
I have a phone where the volume button button flex cable has been partially pulled away from the PCB. See this photo for what it would have looked like before being damaged:

http://guide-images.ifixit.net/igi/noJObJXR2ZSfniZV.large

It's the orange flex cable connection at the center top of that image. There are three connections on the flex cable, the top two have separated from the pcb, the bottom one is still attached.

Can someone advise me what I need to re-solder this? The phone has other problems which may not be fixable so I'd like to attempt this myself as a learning experience rather than sending to a workshop. As well as the partially attached volume flex cable I also have a second identical (but not working) PCB with its volume button still attached. So if I remove that I also have a second chance to solder a volume flex cable to the good PCB if I mess up reconnecting the partially disconnected one.

Some questions that come to mind:

Should I detach the partially detached flex cable completely with a soldering iron? (i.e. separate the remaining third connection on the flex from the PCB), or should I just attempt to re-solder the two broken connections?
The tiny amount of solder that had made the connection on the two broken connections looks to still be attached to the flex cable, can I just try to re-solder by melting this to the pads on the PCB or do I need to remove this from the flex cable and start again with fresh solder?
What kind of solder do I need? Do I need separate flux or just electronics solder wire?

Below is a video of someone doing exactly what I need to do with a near identical PCB and volume button flex cable, but there are no instructions/commentary to elaborate on what the video shows, so I'm not sure if I understand correctly.

The video shows the repair of both a volume flex cable and power button flex cable on a single PCB. First the damaged volume/power flex cables are removed from the PCB, then a good volume flex cable is removed from a donor PCB and attached to the target PCB. Then a good power button flex cable is removed from the donor PCB and attached to the target PCB. In addition to my original three questions above, could you say if my understanding of the different points of the video explained below are correct and answer the queries where I don't understand?

http://www.youtube.com/watch?v=1F6C13O76qk

0:10 Add solder to iron tip, gently remove old volume flex cable with iron tip.

0:30 Clean bare solder pads on PCB by gently scraping with iron tip (and some solder?)

1:01 Apply something to the bare pads with a small paintbrush, glue or flux? If it's glue, what kind?

1:16 Attach volume flex to PCB pads, solder connection (i.e. using the remnants of solder left on the flex cable from its removal from the donor PCB board?)

1:31 Apply some extra new solder if required to make the connection secure?

3:04 Here the power button flex cable is being attached. It looks like before this he has followed the same procedure as with the volume button but then he adds something more with the paintbrush after doing some soldering, and then does some more soldering. What is on the paintbrush at 3:04? Why does he do this in this instance for the power button flex cable but not previously when attaching the volume button flex cable (in that case he added something with the paintbrush to the pads before attaching the flex cable but not halfway through soldering the connection).

If you have any other hints/tips, please let me know. I have to buy the soldering iron and solder and anything else I need (would soldering wick and/or flux be useful for example)? So any other suggestions welcome.

Thanks.


texts: Power Supply - Shorting a cable creates a ground?

texts:
I used a power supply the other day to power an op-amp. I was told to set it up in the following configuration, however I do not completely understand why this works.
The shorted cable acts as ground??


texts: Why do automotive airbag squib drivers support voltages up to 35 V?

texts: I have been looking at several airbag squib drivers lately and I found that most of the squib drivers on the market (such as MC33797 or L9659) have quite large firing voltage range, roughly from 7 to 35 V. I would guess that most of them are suited for 12 V cars so I am wondering why is there this tendency to support such high voltage? What am I missing here?


texts:
I am trying to analyze a transistor circuit. I should find RMS output and input current and voltage. I have made some calculations but I am not sure of whether they are acurate or not.
for input RMS current:
$$
-I_{in} + I_b + \frac{V_{R1} - V_{CC} }{R2} + \frac{V_{R2} - 0}{R_1}  = 0 \\ I_{in} = 4.79\mu A
$$
$$
I_{in(rms)} = \frac{I_{in}}{\sqrt 2} = 3.38\mu A
$$
For output voltage:
I thought the voltage gain is around 3.9 so the output voltage should be Vin.Av and it is 1.14V or 1.17V.
For input voltage:
My signal generator's amplitude is 300mVp so the input signal amplitude should be same.
For output current:
the output current should be \$\beta.I_b\$. Thus \$I_{output} = 1.392mA\$
Here the circuit

Ib = 4.8 micro ampere.
hfe(beta) = 290
Signal generator:
Vp = 300mV
f = 400Hz


texts:
I have problem to get exact GSM location using SIM800L. I have followed instructions in the manual. But my module just gived me latitude = 0 and longitude = 0. This is what I do with my serial terminal.

AT+CGATT=1

OK
AT+SAPBR=3,1,"CONTYPE","GPRS"

OK
AT+SAPBR=3,1,"APN","RCMNET"

OK
AT+SAPBR=1,1

OK
AT+SAPBR=2,1

+SAPBR: 1,1,"10.230.128.34"

OK
AT+CIPGSMLOC=1,1

+CIPGSMLOC: 0,0.000000,0.000000,2020/02/06,03:45:03

OK

I have used another way to solve this problem. This is my another step to get GSM location.

AT+CLBSCFG=0,1

+CLBSCFG: 0,1,""

OK
AT+CLBSCFG=0,2

+CLBSCFG: 0,2,0

OK
AT+CLBS=1,1

+CLBS: 2

OK

With "AT+CLBS=1,1", I still cannot access my SIM800 to get GSM location. This command always give me time out command without any solution.

Why is this happening? How can I solve this problem?


texts: Why aren’t there any “ultra high energy density” batteries on the consumer market?

texts:
I have heard of ultra high energy density lithium cells that boast incredible figures from oxis, sion, and solid energy that blow current li-ion cells out of the water. There are probably even more comapnies out there that I don’t know. But when I try to do digging on them, all I get are generic news articles about the product. And the official websites for these companies say nothing about price. (No listed price = very expensive) I’m surprised that they haven’t creeped out into the consumer market at all. I would suspect that old cells would be down cycled and resold onto the consumer market like many commercial battery packs/modules. I am also surprised that these are not sold to consumers even at a steep premium.

Why are these supposedly ground-breaking cells so seemingly nonexistent and mysterious?


texts:
I try to calculate the ESR of a capacitor.

I checked this datasheet:

http://www.farnell.com/datasheets/2245214.pdf?_ga=2.167304311.817060034.1534770853-676261198.1531404202

I can see from the datasheet for the Aluminum Polymer Capacitors that they specify the max impedance ( Z ) and the tan( δ ) factors

I would like to calculate the ESR for some specific capacitors ( for example 220uF)

Can I just multiply these values in order to get the ESRmax value at 100kHz = tan(δ)* Z ?

Is that correct?

Thanks a lot for your help.


texts: LTSPICE time step to small for (0-5V) to (4-20mA) converter

texts:
i am trying to simulate a (0-5v) to (4-20mA) coverter circuit .when i am trying to the transient analysis of the circuit in the Ltspice i getting a time step error i have kept stop time as 100
for both the transistor
20:gate
10:drain
30:source
i can't figure out what the error is?


texts:
I am working on making a board for the Hummingboard System on Module using the company's board schematic as a guide. They use a TSM2323 mosfet in the "micro SD power on/off" section of their schematic (page 2). As this component is hard to come by I am looking for a replacement MOSFET, but I am not confident in my ability to find a suitable replacement. I would appreciate any suggestions, preferably from Digikey's products.

I found some information online for how to find a replacement MOSFET, but with the sheer number of different MOSFETs to choose from within Digikey's catalog, I am not confident in the replacements I find on my own.


texts: What is the talker ID of this GPS receiver?

texts:
A popular GPS communication protocol is the one specified by NMEA (see here). Communication is done in "sentences", which start with $-- where -- is the talker ID.

Page 18 of the linked specifications gives a list of possible talked IDs. I cannot seem to be able to find the talker ID of my GPS receiver (the datasheet is available here). I expect that it is one of CR, GN, GS or SN, but I don't know for sure.

What is the talker ID of my GPS receiver.

[Note: I am writing test software for a board for which the components only arrive in about 1 month.]


texts:
I know nothing about Atmel Studio other than roughly what it is, and have never used it.

One of the production techs just came to me saying that a shortcut he's clicked for years to program a Atmel doesn't work anymore.  This shortcut runs Atmel Studio 6.  It starts up, displays its splash screen, then after a few seconds barfs on something like "Can't create window".  I figure some software component of Studio or something it relies on got accidentally wiped out on that machine.

I'd like to re-install Studio 6, hoping that the deleted component gets re-installed in the process.  However, I can't find any Studio 6 install file on any reputable site.  I checked the Microchip and Atmel sites, including the "software archive" section of the Microchip site.  The only version of Studio I could find anywhere is 7.

Various web sites out there claim to have Studio 6 installers, but most of them are of questionable heritage.  Element 14 (who I'd trust) claims to have it, but the page is not available when you click on it.  It looks like DigiKey used to have it too, but that it's been taken down.  It almost seems like Microchip has gone out of their way to make Studio 6 unavailable, but that's not been their policy with old versions of MPLAB.

So the question is, Where do I find Atmel Studio 6 installer on a official or highly reputable site?

I can install Studio 7, but I'm worried about some minor incompatibility, plus then someone has to actually know something about Studio to set it up, figure out how to point it to the file to program, etc.  Nobody here, including me, knows anything about Studio, and I'd rather avoid spending the time to delve into it.


texts: Does this simple RF transmitter circuit actually work?

texts:
I've come across this circuit a few times while searching for simple transmitter circuits, and decided to try it.

According to this site, it should be transmitting at around 90Mhz.

http://www.talkingelectronics.com/projects/Spy%20Circuits/SpyCircuits-1.html

I feel like I've followed the instructions to the letter, yet I have no results when chasing the dial on my radio.

UPDATE:

Here are some photos of the circuit I have constructed.

I've tried just about every area of the dial and fiddled with the coils.  No effect or "quiet spot".

UPDATE 2:

I have changed the coil so that it is a single coil tapped at the 6th loop.  I am now getting some effect, but it's not what I expected.

When I pinch the coil together, it seems to drown out whatever FM station I am on.  I can't seem to narrow it down to one frequency.  If I hold the coil together, it will add static or a faint whistling to any station.  The range is also very poor; the phenomena occurs at a max of 3 feet away from my radio with the 12" antenna.  If I use myself as an antenna(holding on to the antenna wire), I can create the effect from the other side of the room.  Is this a good sign or am I fooling myself?

UPDATE 3:

See my answer.


texts:
I am looking to clean up the power supplied to a video transmitter on the UAV I am building. The video transmitter consumes about 200mA of current at 16V DC. The 16V line has noise from motors and other electronics in it. I am using a capacitor to smooth out the current. In the past I would also use a ferrite ring and loop the power cable through it 10 times, and that would really clean up the signal. Now, since I am making a custom PCB for it, I wanted to use a surface mount component that would do the same thing.

Would something like this work?


texts: Diamond: Warning: logical net has no load

texts:
I've a Diamond project with 1 System Verilog module (using Synplify Pro for synthesis) with the code as follows:

module arrtest(clk, led);
input clk;
output reg led = 0;

reg [3:0] arr_index = 0;
reg [7:0] intervals [0:9]  = {8'd125, 8'd128, 8'd200, 8'd210, 8'd192, 8'd192, 8'd185, 8'd100, 8'd255, 8'd80};
reg [7:0] countdown = 0;

reg initialized = 0;

always @(posedge clk)
begin
      countdown <= countdown - 8'd1;

      if(countdown == 0)
      begin
          countdown <= intervals[arr_index];
          arr_index <= (arr_index < 3'd10) ? arr_index + 4'd1 : 4'd0;
          led <= !led;
      end
end

endmodule

And I've receiving the following warnings at the Translate Design stage:

  Running DRC...

  WARNING - logical net 'countdown_cry_0_S0[0]' has no load.
  WARNING - logical net 'countdown_s_0_S1[7]' has no load.
  WARNING - logical net 'countdown_s_0_COUT[7]' has no load.
  WARNING - DRC complete with 3 warnings.

So I'm suspecting that something's wrong in the design and a part of the design doesn't get synthesized.

On the other hand on the Map Trace stage it gives me the following:

  Top 10 highest fanout non-clock nets:
       Net arr_index[0]: 12 loads
       Net arr_index[1]: 12 loads
       Net arr_index[2]: 12 loads
       Net arr_index[3]: 8 loads
       Net countdown6_i: 8 loads
       Net countdown: 4 loads
       Net countdown[4]: 3 loads
       Net countdown[5]: 3 loads
       Net countdown6_3: 2 loads
       Net countdown6_4: 2 loads

And I'm reading it as "the countdown net IS loaded".

Why am I getting these "has no load" warnings and do they mean that a part of the design doesn't get synthesized?


texts: How can i conclude my forward current should be this in LED,opto-coupler?

texts:
1.when design, normal RED LED circuit, Forward current is 20mA. Here, I will select resister for below 20mA and based on that brightness changes.

2.Optocoupler 4N35, ACPL-247 Forward current is 50mA.Based on what parameter I can decide forward current from 0-50mA?


texts: resistor equivalent for non parallel non serial

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What formulas do I need to calculate the resistor equivalent for not just the normal parallel and serial connection?
e.g resistance from A to B og these five resistors:

Is Kirchhoff's laws and hard work my only option?


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I have a 1 MVA diesel generator, 11 kV line to line (medium voltage.)  To test this generating set, I connected it to industrial load (heaters only  with a pf = 1 via a 11 kV to / 380 V transformer.

I now measure that the overall power factor is 0.44 lag and this value is far too low.

Does anyone have any idea of what the problem is?

Here is the transformer data:

Here is the measured result:

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texts: Can the USB module of STM32F103 be clocked by the HSI?

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There is a board of STM32F103CBT6 without external high speed crystal.

I want to use the USB module on this board. The input of the PLL is 4MHZ as I configured PLL source to internal RC oscillator (8MHZ typically with 2x division), then I configures the PLL to 12x, which means the clock to USB module is 48M.

Then the USB module works well, it seems stable.

I tried to heat up the board to 80C to test the stability of the USB module when the accuracy of the clock decreases, I also tried to cool it down to -10C, no problem is caused.

But I still worried about the stability of the USB module driven in this way.

Some datasheet of STM32F0 series from ST emphasizes their usb module is "crystalless", which seems to mean the usb of other series like STM32F1 cannot run without external crystal. But the datasheet of STM32F1 didn't say this problem clearly.

I wondered if usb works really stable enough without external crystal.

BTW, usb is needed to add IAP function to the project, so it is a serious problem.

Thanks.


texts: Help understanding "unusually talked about" transistor code markings

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I am a beginner trying to gain a better understanding of transistor codes. Before posting this, I searched the web looking for answers but I was unsuccessful.

Please take a moment to look at the transistors picture below:

Here are my questions:

Unless I am wrong, all of the transistors on the picture are supposed to represent the 2222 transistor. If this is the case, then why aren’t all those transistors specs identical? Isn't the 2222 supposed to exactly define the transistor properties construction, behavior etc? If yes, shouldn’t all have identical properties?
All of the transistor have a suffix. The first one has “A338”, the second “F42” and the third “B25”. What do those values stand for? If they are specified on the spec sheet could someone please point out to me where because I was not able to find them.
You will notice that the second transistor has a dot or dash before the “F42” and that the third transistor has a dot at the beginning and one at the end of its code. What do those dots / dashes represent?
The third transistor is specially weird (at least to me) because it seems to combine values that the other two do not. Specifically, its first line has the text "P2N2" when I would have have expected to only see the "P2N” text and on the second line the text "2222A". I am assuming they did this due to lack of space which makes me wonder if the dots around the text signify that the code should be read as a single line and not as a multiline?

Thanks for your help.


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So in the A.C distribution network the return conductor which is connected back to the source of the voltage is connected to ground as the theoretical potential of ground is zero the neutral is then zero.

Is that correct?

If so when the current passes the load and returns to the source is it being dissipated to the zero potential sink of earth or is it going back into the source like in a DC battery?

Thanks


texts: Given a transfer function i want an op amp represantation

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I have a project for my university on the transfer function (where a,b,c are constants):

$$G(s)=\frac{(s+a)}{(s^2+bs+c)}$$

and I'm asking how to represent this whole thing with an OPAmp circuit.

(The difficult part that got me the most time thinking, is the numerator)
I would like some help in order to implement it myself and not an immediate  solution.


texts: Evidence for using capacitor-input filters?

texts: Capacitor-input filters are a common thing. However, what is the theory behind this and can someone show me some evidence of before and after using them? I read the wikipedia page on this and it seems a bit technical for a new comer - too many concepts at once. Can anyone care to explain more simply?


texts: How does "delta"-like three phase power source avoid short circuit?

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A delta-like 3-phase power source is as below:

simulate this circuit – Schematic created using CircuitLab

This diagram is equivalent to "Fundamental of Electric Circuits, 5 Edition" Figure 12.6 (b)

Will it be short circuit?


texts: Accurate localization through GPS, IMU and odometry

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I am trying to localize a robot with an error <1m. I have XA1110 GPS but haven't tested it in an open area (due to the ongoing disaster) hence I am unaware of its practically achievable accuracy. I am also planning to fuse the obtained data with IMU and Odometry data through the Kalman Filter for better results.
My questions are:

Does anyone have any recommendations to optimize the approach?
Is this sensor enough to achieve the desired result or I need to upgrade?
Which one would be more suitable considering the budget (50$ USD), RTK or DGPS?

Thank you.


texts: Matlab Simulink interface problem(Simpower Systems vs Simscape)

texts: For my rechargeble  battery model in Simulink,i need a switch that needs to control the voltages across 2 points and according to a certain level it changes its state. To implement this in Simulink i use Voltage-Controlled Switch which belongs to a different library than by cells whose voltages are 12 Volts each. After connecting "Voltage-Current Interface(Ground)" to my circuit  to connect these two objects of two different libraries i get an error stating the following. How can i fix this problem. Do you have any suggestions that i can do to accomplish my task. You can find the design and the error message below.