texts: Reduced gain with ground loop isolation with car aux head unit

texts:
How to suppress ground loop hum without reducing audio gain?

I added an aux input to my car's factory head unit by soldering wires onto pin 4 (right channel) and pin 33 (left channel) of the M62490FP chip as per the forum instructions. For ground, I soldered a wire to a part of the metal casing, which I suspect is the problem. These wires then go to a female 3.5mm aux input.

Problem is the input is noisy and playing music from a phone while charging from the 12V DC output produces a terrible ground loop hum. To address this, I added a ground loop isolator component between my phone and the chip. This fixes the hum, but kills the gain, making it too soft. Circuit from the forum (except for ground):

Now I'm stuck with a loud noisy system, or a clean radio that's way too soft. As I understand it, a ground loop is caused by kind of resonance or improper grounding.

Does it matter where on the head unit different components are grounded? To my limited knowledge, it should not matter as long as there is continuity between circuit nodes.

The car is a Subaru Forester 2007. Complication is that I am essentially overriding the CD mode and need a silent audio CD to not interfere with the aux input. Other hobbyists report this working perfectly.

Circuit Diagram:


texts:
I found this little device which got my attention. Maybe you can tell me what it is. Is it a I/O board with an OS running on it similar to Raspberry PI?

ICs on the device:

AMD: AM29F200BT-70EC "Boot Sector Flash Memory"
2x HYUNDAI: HY628100B "128Kx8bit CMOS SRAM"
SIPEX: SP232ACN "Enhanced RS-232 Line Drivers/Receivers"
Lattice: GAL16V8 "High Performance E²CMOS PLD"
Infineon: SAF-C164CI-LM "16-Bit Single-Chip Microcontroller"

Top:

Bottom:


texts: Programmer/debugger options for microchip's eval board

texts: I recently received a CEC1x01 eval board as a part of free hardware to develop solutions for a competition. My issue is regarding programming the board. They only shipped the eval kit and no hardware programmer was included with it. I do not have a segger J-link and I guess buying one would ultimately defeat the purpose of 'free-hardware'. I however had been working with stm32 microcontrollers and have a 'blue pill'-turned-'black magic probe' that supports jtag. I tried connecting it to the board and used arm-gdb to scan it, but the jtag-scan returns error, and the board is not recognized. What are my options here?


texts: Can an optical mouse sensor chip (System On Chip) which has a digital signal processor, Serial I/O, and a set of registers be considered as a Micro-controller?


texts: What are some ways to extend life of Nixie Tube?

texts:
I'm working on a Nixie tube clock and have read that nixie tubes have a life of about a year.
Does anyone know of ways to extend the lifetime of a tube?

Can you use a mosfet to switch the high voltage power supply using PWM or would that just end up delivering a lower average voltage?

Specifically I'm using IN-14 Tubes, and plan on driving them with 170VDC, 3mA.

Any input is appreciated! Thanks!


texts: USB TYPE-C ALT-MODE DisplayPort + USB 2.0, is it supported?

texts:
DipslayPort 4 lanes are supported through usb type-c alternate mode. USB power delivery and usb 2.0 is always supported with the displayport alternate mode.

Powerdelivery is not crucial however usb is so critical for me. I need a passive type-c dp output with a usb 2.0. However I cannot find any low cost passive type c converter with these features.

According to this paper it should be possible:
https://www.vesa.org/wp-content/uploads/2016/10/USB-DevDays-DisplayPort-Alternate-Mode-2016-final4.pdf

Do I understand something wrong? Does anybody know any kind of schematic that I can make this at least by myself?

Thanks


texts: 36V inductive charging coil or multiple coils

texts:
I want to charge a 36V lithium battery using an inductive charging setup, input 36V and output 36V. Currently I am charging at 2 amps, so along those lines. I can only find coils online that work up to 12V. I have seen a product that can output 36V, but I cant find the components to build it.
Would wiring 3 x 12V in series work, or would the charging fields cause problems?
All ideas welcome.


texts: Confusion regarding PRESET and not(PRESET)

texts:
After watching the video explanation (https://www.youtube.com/watch?v=mXoQ4WAQ0qk) regarding PRESET and CLEAR . I have made following conclusions .

Considering Active Low / bubbled case as shown below image

Whenever CLEAR is 0 implies output Q is  0
Whenever PRESET is 0 implies output Q is  1

So Is  it correct to conclude that

Whenver not(PRESET) is 1 implies output Q is 0
Whenever not(CLEAR) is 1 implies output Q is  1

[![enter image description here][3]][3]

Or in other words is it correct to conclude

PRESET  is 0 implies output Q is 1 , not(PRESET) is not(0) i.e 1(WHENEVER ACTIVE LOW/BUBBLED)
not(PRESET)  is 0 implies PRESET is not(0) i.e 1 , Q is 1 (WHENEVER ACTIVE HIGH/not BUBBLED)


texts: Accurate yet relatively simple way to use RTD probes

texts:
I would like to build a reference thermometer for checking and maybe calibrating other sensors and I was planning to use 1/10 DIN RTD probe in order to do that. You can get such probes for ~$100 and the error is ≤±0.07C in -50°C - 50°C range, which sounds great. I'm not sure, however, if I can use it efficiently without deep electronics knowledge or spending a few hundred dollars on a reference thermometer like Fluke 1523.

The easiest (and pretty cheap) way to use RTDs is MAX31865 (IC to automatically convert RTD resistance to temperature readings), but the only note about accuracy that I can find on it is this line from the datasheet "Total Accuracy Over All Operating Conditions: 0.5°C (0.05% of Full Scale) max". 0.5°C full scale doesn't sound bad, but I'm not really sure what that means for lower temperature ranges, for example: how much the error of the RTD will increase in the 0-100°C range when using MAX31865. Without that knowledge I also don't know how much do I gain by using 1/10DIN instead of Class B probe.

So my general question is: what's the easiest way to accurately read precision RTD probes with a limited budget (like $50-$100 not including the probe)?


texts: Has anyone seen power cycle corruption in industrial SD cards?

texts:
I am using a micro SD card in a new embedded Linux system (choice of SD was not mine, was made by the hardware guys).  I have seen a problem before where power cycling of a system without doing a proper shutdown has resulted in the SD card being unusable - yes even reformatting it didn't revive it.

I was wondering if anyone has seen this type of failure in industrial rated SD cards, as they're apparently designed to handle sudden power failure better.


texts:
So i need to perform analysis of simple astable multivibrator circuit shown in the following picture:

These Vdd and GND are just the power rails of those CMOS inverters.

Now, i need to perform analysis, so i have three characteristic points here: point 1) input to first not gate
point 2) output of 1st not gate (input to the 2nd not gate at the same time)
point 3) output of 2nd not gate

We want to determine the period of oscillation

Assume that we have high state at the 2nd point, then we have the following circuit (I've neglected the effect of output resistances of inverters since i consider them too small comparing to R1)

Now, well known expression for voltage of point 1) which can be derived from solution of differential equation of this circuit is:

$$V_1(t)= V_1(\infty) - (V_1(\infty) - V_1(0)) e^{-\frac{t}{R_1C_1}} $$
Now, i am supposed to know the starting value of V_1, but i determine what it should be, at the infnity, it should be Vdd since it cant go beyond that, but i cannot determine the starting value of V1, so any help is appreciated!


texts: Splitting Variable of integer into 2 Set

texts:
I have actually 2 issue in code.

1) variable declaration. I have declare variable
unsigned int Top_Display=0;
if assign Top_Display=0123 display shows 0083
if assign Top_Display=123 display shows 0123
Some of the variable it take properly and some are not. if i assign value Top_Display=0129 it gives error digit is out of range.

2)i have created 1ms timer interrupt . every 1ms i am increment msec . i am getting wrong calculation for displaying Msec to sec. other paramter it showing well. somewhere the conversion is affected

1S=1000ms
60S=1Min
60M=1H

      unsigned char LED_MS_Flag=0;
    unsigned char LED_SeMi_Flag=0;
    unsigned char LED_HM_Flag=0;
unsigned char Main_Flag=0;
unsigned char j=0;
 int Bottom_Value=0;
 unsigned int Top_Display=0;
unsigned int Float_Value;
unsigned int InG_value;
unsigned char LEDBuffer_1[8];

unsigned int Hour=0;
unsigned int Min=0;
unsigned int Sec=0;
unsigned int MSec=0;
const unsigned char DISPTABLE[28] = {0x03,0x9F,0x25,0x0D,0x99,0x49,0x41,0x1F,0x01,0x09,0x11,0x83,0x31,
                                      //0  //1  //2  //3  //4  //5  //6  //7  //8  //9  //A  //U  //P
                                     0xD1,0xE3,0x89,0x63,0xE1,0xF5,0xC1,0x61,0x71,0xF3,0xFD,0xD5,0x85,0xFF,0X43};
                                      //h  //L  //Y  //C  //t  //r  //b   //E //F  //I  //-  //n //d  //blank //G
unsigned char Blink_Count=1;
unsigned char Converted_Value;
unsigned int Top_Value=0;
unsigned char EEPROM_Write_Flag=0;

unsigned char EEPROM_Read_Flag=1;
unsigned int Result;

void Process_RUN_MODE() {
    if(EEPROM_Read_Flag==1) {
        //READ_EPROM();
        EEPROM_Read_Flag=0;
    }
    Top_Display=(int)1123;

    LED_MS_Flag=1;
    if(LED_MS_Flag==1) {

        LED_HM_Flag=0;//min_Hour Flag
        LED_SeMi_Flag=0;// Sec & min FLag
        LED_MS=1;
        LED_SS=0;
        LED_HM=1;
        Dissect(Top_Display);
        DelayMs(10);
        Dissect_2(Bottom_Value);
    } else if(LED_HM_Flag==1) {
        LED_SeMi_Flag=0;//sec & min flag
        LED_MS_Flag=0;//Sec_ms Flag
        LED_HM=0;
        LED_MS=1;
        LED_SS=1;
        Dissect(Top_Display);
        Dissect_2(Bottom_Value);
    } else if(LED_SeMi_Flag==1) {
        LED_HM_Flag=0;//min_Hour Flag
        LED_MS_Flag=0;
        LED_SS=1;
        LED_MS=0;
        LED_HM=1;
        Dissect(Top_Display);
        Dissect_2(Bottom_Value);
    }

}

void interrupt isr(void) {

    asm("clrwdt");

    if (TMR1IF) {
        TMR1IF = 0;
        //  TMR1H = 0x3C;
        //  TMR1L = 0xB0;100ms

        TMR1H = 0xFE;
        TMR1L = 0x0C;// timer interrupt for 1ms
        if(Top_Display>Bottom_Value) {
            if(LED_MS_Flag==1) {
                Bottom_Value=(Sec*100)+MSec;
            } else if(LED_SeMi_Flag==1) {
                Bottom_Value=(Min*100)+Sec;
            } else if(LED_HM_Flag==1) {
                Bottom_Value=(Hour*100)+Min;
            }

        } else if(Top_Display==Bottom_Value) {

        }
        MSec++;
        if(MSec>1000) {
            MSec=0;
            Sec=Sec+1;
        }
        if(Sec>=59) {
            Sec=0;
            Min=Min+1;
        }
        if(Min>=59) {
            Min=0;
            Hour=Hour+1;
        }
        if(Hour>99) {
            Hour=0;
        }
        Display();
    }

}

}
Void main()
 {

  while(1)
   {
Process_RUN_MODE();
  }

}

void Dissect_2(unsigned int Value)              // Spliting of process value in digits form
 {
    unsigned char a,Temp;
    for(a = 4;a >= 1 ; a--)
    {

     Temp = Value%10;
     Value = Value/10;
     LEDBuffer_1[a-1] = DISPTABLE[Temp];

    }

 }

void Dissect(unsigned int Value)            // Spliting of process value in digits form
 {
    unsigned char a,Temp;

    for(a = 8;a >= 5 ; a--)
    {
     Temp = Value%10;
     Value = Value/10;
     LEDBuffer_1[a-1] = DISPTABLE[Temp];

    }

 }


texts: Question about Third order Butterworth Filter Design

texts:
I'm new to PSpice and filter design and I'm trying to design a third order Low pass Butterworth Filter with cut-off frequency = 10 Hz. Here is the circuit that I've designed:

I've applied a 5V sinusoid with 2V DC offset to check whether it is working or not. Here is the result that I'm obtaining:

At the output I should get 2V, which is exactly the DC component of the sinusoid that I want, correct? However, I have no idea why it is taking so long for the output to settle into 2V (~ 0.2 seconds). Is there any way I can improve this design in order to minimize this stabilization time? Furthermore, could someone provide me some recommendation on which OP AMP comercially available models it is best to use for filtering?
Thanks for your attention.


texts: Is electric power equal to its radiant flux?

texts: I just want to ask, is electric power equal to radiant flux? In calculating intensity, it is the total light power emitted (radiant flux) divided by the surface unit area.


texts:
My friend accidently stepped on a wire for his light and the tension broke the adapter's connector - I told him I'd try to fix it. I've already cut the connector off and have readied my replacement. I plan to use solderless connectors but as the original connector colors are unfamiliar I want to check with this site about how to check for which wire is power and which is ground.

Can I use my multimeter to check which wire is power and which is ground? If so what setting do I need to use?

The adapter:

The new connector:


texts:
I do understand why when drain voltage (\$V_D\$) increases, the channel carriers decrease (the channel narrows), specially near the drain island, eventually reaching pinch-off phase.

What I don't get is why the depletion region is supposed to widen, as (\$V_D\$) increases.


texts: For the paper named "Antenna Miniaturization and Bandwidth Enhancement Using a Reactive Impedance Substrate" the statement "PEC-backed dielectric material", so what is the meaning of this statement? Is it a normal substrate?


texts: Why are SMD LEDs shipped in a sealed bag containing desiccant?

texts:
I had a selection of 0805 LEDs in my last Mouser order and was a bit surprised to discover they arrived in heat-sealed (rather than folded and taped with sticker) bags containing a desiccant bag and some sort of litmus-esque paper indicator saying something about baking them if the dots on it went pink (instead of blue).

A quantity of through-hole LEDs I had in the same order just came in the regular ESD-protective bag, folded over with a sticker.

What's up with SMD LEDs that they work so hard to keep them dry? Surely their dryness can't be assured once they're installed. Does it have to do with their solderability or something? Why would that be different than other SMD parts?


texts: Importing Altium schematics to a PCB is placing some components on a forbidden and an unaccessible area

texts:
I was using Altium 16 and generating PCB from schematics with no room generation. I have created my components library by mostly using "ultra librarian" files. I do these steps as many other times with no problems.
After this, I first run "design/update PCB doc.." from schematic view and when the process has ended my pcb components generation has this view:

As you can see, some components have fallen out of allowed display and I can not achieve the most of them in order to drop up them into an allowed area.
I have noticed that there are some components that are put under origin coordinates, so it is the maximum that display can achieve. It can not go down origini coordinates.
I have also noticed that some components has the designator is placed so far from its component footprint.
I removed the pcb document and restart the traslation, but no changes happened.
I build a new project using the libs and schematic and start the traslation, but it results with the same way.

Have this happened to someone else?

Why can it be happening? Is it a sw bug?

How can it be solved in order to move and place the components from there?

Giving me some hints could be helpful for me.


texts: Is there a way to have the .Designator string in the component footprint center on the component? Designator string R1 will look left-justified on the component (which it is), and string R11 will seem centered simply because it's 3 characters long. It would just look a lot neater if it was center justified.


texts: I'm studying computer architecture and I wonder why the inverter is needed in this ALU?


texts: What's wrong with this single-transistor level-shifter?

texts:
I was trying to step up the output of a 3.3V microcontroller pin to 5V for communication with another device. I wanted to do it with a single bjt, and found a good design for doing that here

Single transistor level up shifter

That design works fine and I've moved on with the project, but it left me with a question: Before I went looking for a design online, I assumed I could just flip the resistor on a standard logic-inverting level changer from the high side of the transistor to the low side. i.e. I tried this

simulate this circuit – Schematic created using CircuitLab

It seemed like a pretty straightforward switch. At LOW input, I thought the transistor would be off and the output pulled to 0V, and at HIGH the transistor would be active and connecting Vout to 5V. The HIGH part of the plan didn't work, though. A 3.3V input to the base brought Vout into the neighborhood of 2V, with 3V dropped across the transistor itself.

I don't have a lot of breadboarding experience, so I'm sure there's a simple explanation that I'm missing here. If anyone could enlighten me as to what's going on, it would be much appreciated!


texts: Replacement Transistor for Ultrasound Cleaner

texts:
I'm trying to repair the generator board on a Sonix IV ultrasound cleaner. I need to find a replacement for a transistor (in a TO-3 package), but the manufacturer uses an in-house part id, so I'm trying to figure out what kind of transistor this is.

This guy has a similar problem, but a slightly different generator board:
Replacing a transistor when I can't find any info on it. I suspect it is the same transistor though. Like him, the manufacturer is unwilling to give information about the part.

I have tracked the part-placement and wiring on the board, and created a schematic. Can anybody use this to suggest a suitable replacement part?

Schematic:

Board:

Top layer PCB:

Bottom layer PCB:

Silkscreen:


texts:
I'm using this DC-DC converter  +/-5V output version and I decided to use the trim up setting to get as close to 5.5V as possible. I determined the resistor value using this formula
And got around 3.33k, which gives me about +5.56V and -5.59V. However in the datasheet it has a "Voltage adjustment range" part where it has +/-10% for dual output models, which means I can get a maximum of +/-5.5V output.

Obviously I'm getting that (and a bit over), but my question is whether meeting the maximum settings of a DC-DC converter can cause any issues?
Are there potential problems with 'stretching' such converters?
Would they draw more current, drain the battery faster?

Battery input is a Li-Ion 14.4V.

I need this to be around 5.5V because it goes into 2 LDOs that drop the voltage to ~5V (+/-), because as I understand, the greater the difference between intput/output for LDOs, the better their operation (?).


texts: Why is this opamp PWM circuit not giving a PWM output?

texts:
I thought I'd see a PWM rectangular wave at opamp output, but the simulation gives a constant +Vsat.
Why am I not getting PWM ?

simulate this circuit – Schematic created using CircuitLab

EDIT: After fixing VEE error pointed out by Transistor, still not getting the clean PWM output:(

EDIT: changing opamp to TL072 as suggested by G36 in the comments fixed the issue:


texts: H bridge for peltier heating and cooling

texts:
I am testing DRV8840 circuit in my setup as a 12V, 3amp peltier controller.

And there are 3 temperature set points : 25, 30, 37 celcius.

Hardware configuration done so far as follows:

Trial 1 :

purpose: heating of peltier from 25 to 37 celcius
Enable = Logic 1 (5V), Phase = logic 1, decay = 1 R Sense = 0
observation: initial temp 30 and reached 37 after 5 mins ( ok as per our requirement)

Trial 2 :

purpose: cooling of peltier from set point 37 to 25 celcius ,
Enable = logic 1, phase = logic 0, decay = 1 , R sense = 0,
observation : taking 30+ mins for reaching required set point 25 celcius from 37 celcius

Trial 3

purpose: cooling from 37 to 25 with driver off,
Enable = logic 0
observation: 30+ mins for reaching
30+ mins for 25 setpoint from 37 is too much , 15 mins waiting time is ok.

For heating Phase pin status = Logic "1" and for cooling phase pin = Logic "0"

So can anyone suggest why cooling taking so much time 30+ mins and way to do fast cooling? (15-20 mins duration ok)


texts: Transformless power supply without ground

texts:
I would like to make a transformerless power supply, I found some description on the Internet like this pdf provided by Microchip. My question is it is possible to use only the phase line(without neutral line) to build a transformerless power supply and power up a microcontroller, for example in the wall mounted light switch I have only the phase.
This is what I found on the Internet, there is only two wire.
EDITED

I just order one of this bulb dimmer, here is a few picture:

And inside the cover:

It seams that there aren't a battery, how is it possible that this circuit is working?


texts: Relay to switch 24v dc (low current) with 240v ac mains?

texts:
I have a 240v AC main (switched) and wish to control a 24v DC logic with it.

Background: I bought a cheap WiFi enabled (Broadlink chip) thermostat to control my central heating.  It's a surprisingly decent unit.  However, up on receiving it I realised the output is switched mains, whereas the logic board on the boiler (Ferroli) is 24v DC.

What is the easiest/cheapest way to achieve this?

Thanks

[Note- I realise this is the converse of the typical switching scenario wants and clearly the "cleanest" solution would be return the controller and get a more appropriate one!]


texts:
I am an amateur radio operator, and often provide communications for events and train/prepare for communications in the event of a disaster (earthquake, flood, etc.).  As part of this, I'm building a box that will contain a mobile radio, two AGM batteries, and provide power to charge hand-held radios.  The load could be as high as 20A, and all devices expect a nominal 13.8V, typically specified to +/- 15%.

In order to extend runtime and provide more flexibility, I'd like to provide a power in connection on this box.  This might come off a well-regulated 13.8V power supply, off a car "auxiliary" power socket, or any other ~12V power supply.  My first thought is just to put the input across the batteries and load and let the input float the batteries and power the load, but if the voltage of the source drops below the voltage of my AGMs, I'd be feeding power back into the source.  Hopefully that won't be a car trying to start!

So my next thought is to put a schottky diode on the input port (and hope that I don't inadvertently connect to the output ports) but that means I've now lost ~.4V from an already unknown power supply.  I'd also like to be able to periodically connect a "proper" charger to this port, and I'm not sure how those smart chargers would handle a schottky in the way.  I'd suspect they'd undercharge the batteries, since the voltage at the battery would be lower than the voltage at the source.

I'm more concerned about flexibility than about prolonging the life of the batteries, they'll likely be a pair of 7 or 10AH SLAs, so only ~$40 of battery.  There are commercial devices that might help, like the Super PWRGate but it seems overkill to put $140 of hardware to this.  Is there a simpler/cheaper approach?


texts: relation between com port, jtag and uart

texts: can somebody please explain what is the relation between those terms. I tried to find some info in wikipedia, but there is no word about relation between those technologies, thanks in advance for any good abstraction or link


texts: A question about capacitor type and temperature limits

texts:
Is it possible for a 100u or 10u electrolytic capacitor to operate at -30C ambient temperature?

What type of capacitors can this be replaced for such low temperatures to operate fine and better stability?


texts:
I am laying out an ADuM260N digital isolator. There is some higher frequency switching (~20MHz) on other components also connected to the input (left) voltage rail. I read this thread on decoupling, but there doesn't seem to be any consensus on the best via layout, specifically whether to connect the vias to the IC pin or the capacitor pin.
After reading the grounding sections of Ott's Electromagnetic Compatibility Engineering, two takeaways are:

Add multiple vias to power/ground to reduce loop inductance
Reduce mutual inductance by spacing out vias carrying current in the same direction (eg. GND and GND), and by moving vias closer that carry current in opposite directions (eg. PWR and GND)

From these takeaways, my attempted layout is below:

This is the datasheet's recommended layout:

From this, I have a few questions:

Should I be connecting the vias of the 5V nets to the IC pin or to the capacitor pin?
Could using two vias per net in this way somehow harm EMI/EMC performance?
Is the datasheet recommendation of connecting the decoupling capacitor GND across the IC directly to the GND pin of the IC, a good idea?

Thanks!


texts:
I am using an instrumentation amp (http://www.linear.com/product/LT1168), and I am a bit confused why it is giving me a output voltage that I am not expecting.

I am pretty sure, I am doing something dumb here.

The way I have it hooked up now is as follows:

I am expecting a 5V difference between the reference and the OUT pin, but I am only getting 3.9. What am I doing wrong here?  I know the output will not go to the ramp voltage, but 3.9 seems too little.

There must be something I am missing.
Datasheet: here


texts: Would this be the correct diagram for wiring LEDs with different voltages?

texts:
Since I haven't dealt with voltages/current/etc since highschool, I'm not super confident in my abilities to not blow up a bunch of LEDs - I read a few guides, but would appreciate if someone could confirm I'm on the right track!
I'm using two 9v batteries adding up to 18v to power the system, and running 10 LEDs in 5 groups (2 2.2v, and 3 3.2v). The total voltage adds up to 14v, so my logic follows that if I use Ohm's Law on the two groups running 2.2v at 20mA, I need a 100 Ohm resistor on both to eat up the remaining 4v (2/0.02 = 100).

Would I be correct in my logic, or is there something I'm missing? Any guidance would be very appreciated!


texts:
I'm trying to study DAC .. In my reference text book the equation is given as follows

On some online sources 2 is given as the subscript.Please see

https://www.allsyllabus.com/aj/note/ECE/LINEAR_ICs_and_APPLICATIONS/unit4/BINARY-WEIGHTED%20RESISTOR%20DAC.php#.WnQT2DNX7qA

I was wondering if my text book is correct.


texts: Does CSR1012 need an external non-volatile memory for this application?

texts:
I am building a IoT device in which  data is fed from I2C to CSR1012 BLE IC and the CSR1012 then transmits the data. CSR1012 is programmed as a master MCU.
I need over-the-air update capability to push any future firmware update on this device. I am not clear on whether or not I need an external non-volatile memory like EEPROM or I2C flash to make implement over-the-air firmware update feature.
This is just to ensure that if i need to push firmware updates, I do not need to physically connect these devices to a computer.


texts: Understanding optical parameters of image sensors

texts:
I noticed that image sensor manufacturers provide some optical characteristics in different formats. I wish to know how to interpret that information.

Sensitivity is characterized in \$\dfrac{V}{lx \cdot s}\$ for S11639 and TCD1201, which is \$\dfrac{V}{J \cdot s/m^2}\$. At the same time, RL1024P and S10077 report sensitivity in \$\dfrac{V}{J/m^2}\$. Now time 's' is gone from the characteristic. How do I interpret this characteristic in terms of light intensity and exposure time?
Conversion efficiency seems to be obvious - voltage increase per every additional electron. Is this related to sensitivity in any way, or it just gives the resolution and range of the output voltage?
Dynamic range - is it also the 'output' characteristic and has nothing to do with optical characteristics of the device?

It would be nice to have an extensive explanation for each term and how it is related to each other. What set of characteristics is preferable, what are the compromises. Any additional parameters that are worth mentioning?

EDIT:

Also, how do I convert Aviiva M2CL sensitivity that is reported in digital format to analog format, form \$\dfrac{LSB}{nJ/cm^2}\$ to \$\dfrac{V}{nJ/cm^2}\$


texts: What should a 12v solar battery read while in use?

texts:
I have a 12v solar system with 2 12v batteries (One marine, other a car battery).
My inverter has a minimum voltage input of 11.0v and peak of 15.0v, but when I'm running it under load, I get a voltage of 10.9v - 11.8v, and 12v-14v when not underload.
Is there something wrong with my setup or is this normal for a battery under load?
btw, the panels are 20v and charging the batteries while under load as well as not under load. (Charging current :500mA, solar panel current 7A.)


texts: I have usually noticed that when ceiling fan of room is turned on, the screen of monitor or LCD goes black for a moment. Why is it? and It resumes from the same point i.e only monitor goes off and computer doesn't because otherwise the system should be restarting.


texts: Determining The Polarity of a FeedBack Circuit

texts:
In determining the polarity of such a circuit I used the following reasoning:

if Vin goes up ID1 goes up and ID2 goes down, ID4 goes down and VG3,VG4 go up because of PMOS, then Vout goes down, if Vout goes down then Vin will go up. So I ended up with positive feedback. Am I making a mistake? Sometimes when I try to understand a current source's relationship with its nodes polarities I get confused. Could you explain this point too?


texts:
I know this is a current mirror circuit, which means that Io should be equal to Iref = 0.25 mA.
I made it in a simulation program and it shows that current only flows through the first transistor (from the left.) Why is that?
In the simulation program I connected Io to ground, because I didn't really know why it is 'floating' like that. Hope some of you might know.


texts:
I got an old RF circuit (I guess), probably used for pedagogical purposes.
Here's the schematic:

I chose the positive and ground rails as it seems right to me, looking at transistors and resistor values. But I could be very wrong, because there are no wires/labels at all. The three unnamed transistors are 2N2923s. Resistors at the output of 3a and 3b are 470k.

It looks like an RF transmitter to me, maybe FM.

Is the block n°1 a known topology? If so, what's its name? Where should the antenna be connected? Is the crystal oscillator fixing the carrier frequency at 27.120 MHz?

Moreover, I'm puzzled by the blocks 3a and 3b. Are they input(s)? Why are there two nearly (different resistors values) symmetrical blocks? Again, I have absolutely no clue on where the inputs should be (no wire or obvious terminals).

Finally, if I'm right on the power rails, is there a safe voltage I could apply to test the circuit? The 20 µF capacitor is rated for 10 V.

Here's the physical circuit:

Edit:

Regardless of the applied voltage (between 2V and 8V) I can't manage to make the two phase-shift oscillators oscillate.

But the RF oscillator works fine! I measure a frequency of \$28\pm2 \text{MHz}\$ with an oscilloscope. This is what I get when I directly probe the 2N1711's collector (0.8 Vpp when powered at 8 V, with the variable capacitor properly tuned):

However, I can make it modulate when I apply a signal on the base of the transistor in block n°2 through a resistor. At best (adjusting signal frequency and amplitude), I manage to get a pretty good modulation (at the bottom, the TTL output of my generator):

Edit 2:

After replacing the 22 µF capacitors, the phase-shift oscillators works. At 6V, the 3a oscillate between 2.86 kHz and 2.30 kHz, and the 3b between 3.08 kHz and 5.08 kHz.


texts:
I'm living off the grid in the bush in a hut I've built since this whole virus drama.

My only issue is I'm not really good with electrical stuff. By this I mean I have a few basic solar set ups that I'm trying my best to get working. One gives me enough power to run a small light in my kitchen which is ok for that purpose but could be better.

The one that I've started working on has eight small 12 volt rechargable batteries. I was able to wire them all together and then wire them to a small solar panel and fully recharge them all today.

My main question is what would be the best lighting system ie LEDs, wire up a standard light fitting???

How much running time would I get off such a set up? I just need some good bright light during the evening to do some craftwork under.


texts:
Background:
I am trying to design a battery powered gate opener, the basic concept is that if the uC switch is on the relay switches the motor on, but if the actuator gives a low feedback (gate is fully open) I want the motor to stop i.e. it overrides the other switch. This all works however when both switched are open it should not draw power however it actually draws 11.772mA which I just can't work out how.
In the diagram below Pink is power Blue is current.
The complication with this is that as well as switch of the actuator when gate is open I also want to signal to uC that it is open so the uC will have a pull up resistor in place and listen for when it is pulled low. That is represented by V3 and R6.
I don't understand how 11.772mA goes from V2 through R4 then the relay and Q1(BC547B) NPN to ground??
And how is the base of Q1 715mV??
If it helps the simulation says NPN Q1 is also HOT??

Thanks in advance for your help.


texts: Reception voids with two omni antennas at 90 degrees

texts:
We are using two omni ferrite rod antennas to transmit a signal at 125 KHz. The two antennas are positioned at 90 degrees from each other on the PCB plain, and the device installation is with the PCB parallel to the ground. The device will typically be installed on the ceiling, so we'd like to have good reception in a half-sphere around the device, to the sides and towards the floor.

The mobile receiver also uses two ferrite antennas that are at 90 degrees from each other. Naturally the orientation of the receiver with respect to the transmitter can change.

Overall reception of the 125 KHz signal is good, at about 5-6 meters, but we have some voids. In these voids reception drops to around 0.5-1.5 meters.

These voids are at roughly 45 degrees to the transmitter antennas, but we haven't mapped them all yet:

Can anyone give some clues as to why we would have these voids? In theory, having two transmitter omni antennas should cover all voids, no? Perhaps the angle between the antennas should be changed?

Edit: the transmission signal is wired in series to the two antennas. On the receiver side the receiver is wired separately to both antennas (i.e. not in parallel).

Edit 2: two more observations:

Disabling one of the receiver's antenna seem to improve reception.
On the other side of the 45° void (i.e. 180° from it) reception is better, almost as good as in the rest of the field.


texts: Back to back Schottky diodes between ground connections

texts:
In a mixed-signal IC, you most likely will have two ground planes, analog ground and digital ground.  This seems fair enough and easily understandable but my real question is:  Why would you need to insert back to back Schottky diodes between two grounds?  What purpose would they serve if the ground places are already separated?  No coupling should occur if the designer properly managed to split the planes.

Here is a picture of what I am trying to get information about:


texts: Closed current loop control without H-Bridge, PWM

texts:
I am trying to find a way how to control the Voice Coil Motor (VCM) or PMSM motor with a closed current loop without the use of an H-Bridge & PWM.
Does anyone know how to make an analog closed current loop control without PWM and H-Bridge?
I heard that the closed current loop was the last from the cascade control scheme to be digitized and I'd like to compare the performances of analog versus digital one.


texts: How to let Quartus generate VHDL out of Qsys automatically

texts:
I was wondering how I can get Quartus to automatically generate VHDL IP from Qsys files, instead of the default Verilog.
I know I can change this in the command line or Platform Designer GUI for each Qsys block. However, I want to get it to work such that any designer using my project file doesn't need to open a lot of platform designer GUIs, to let the flow generate VHDL instead of Verilog.
I tried to change the following line in the Qsys files, but this does not look to have any effect:
<parameter name="hdlLanguage" value="VHDL" />


texts: piezo and 3v LED in series to 3v battery

texts: I'm a complete newbie to electronics.  This piezo I have works with a 3v battery, and this green 3v LED works with the 3v battery, but when I combine both the piezo and LED in series on the 3V battery, neither of them work.  I know both the piezo and LED are omni directional, but even when I turn around the LED and try the battery both ways around it's not working. It should be so simple, how do I get this to work?


texts: PIC10F200 - blinking LED (pic-as) - Assembly

texts:
The code below worked for my 10F206, but now I use a 10F200 and for some reason the led
does not blink anymore.  (compiler: pic-as 2.30, IDE: MPLAB X IDE 5.40)
It compiles but the led stays off.
When I use the simulator and debug the program and step over with F8
it jumps to the first instruction after the label "Start" after calling the subroutine "Delay".
I deleted the line with the cmcon0 register, because the PIC10F200 doesn't have a comparator in contrast to the PIC10F206, but it does not help.
    PROCESSOR   10F200
    PAGEWIDTH   132
    RADIX       dec

    #include <xc.inc>

    config MCLRE = OFF
    config CP = OFF
    config WDTE = OFF

    PSECT   StartCode,class=CODE,delta=2
    global  Start

Start:
    movlw 11000000B
    option      ;to turn off T0CKI

    movlw 00000000B  ;center frequency and turn fosc4 off
    movwf 05h        ;to turn off FOSC4 from GPI2
    ;osccal register is at 05h

    movlw 01110001B  ;bit 3 to 0 for turning comparator off
    movwf 07h
    ;cmcon0 is at 07h, but it doesn't appear in the special function register

    movlw 11111101B  ;set GP1 to output direction
    tris 6

Loop:
    BCF 06h,1
    ;gpio is at 06h ;GP1 is bit 1 (could also try 01h)
    call Delay
    BSF 06h,1 ;turn LED off again
    call Delay
    goto Loop ;loop forever

Delay:
    movlw 100  ;put the decimal number 100 into w
    movwf 11h  ;put 100 in register 0Ah
    ;register 11h should be general purpose register that I can use
    ;to put in values
    movwf 12h
    ;put 100 in 12h
Delay_Loop:
    DECFSZ 11h, 1
    ;decrement the register and store the result in itself
    ;and skip the next instruction if the result was zero
    goto Delay_Loop

    DECFSZ 12h, 1
    ;the same with the second register that I filled
    goto Delay_Loop
    retlw 0

end Start
```


texts: usual unloaded load cell diagonal voltage?

texts:
I found a load cell and wonder if its working or damaged since the diagonal voltage is not zero with no load on it. The diagonal voltage is about two volts when I supply 5 volts. There are no stickers on the cell only a handwriting which says 200kg so I didn't have a datasheet.

My research:
I read that the diagonal voltage changes usually about 2 to 10mV per supplied volt when changing the load from 0kg to full load depending on the cell. I didn't find any information about the voltage level itself only about the change.

My thoughts:
However 2V seems too high because a differential OpAmp with a gain higher then 2 could be easily out of range. While a gain of 2 is too low since 10mV should be amplified with 100 or so to get proper reading on a voltage measurement device.

So the question is:
What is the usual range of load cell diagonal voltages?


texts: As a capacitor is charging in a circuit with a battery as the power source where is the source of electrons coming from?

texts:
I have edited my explanation.  I hope this helps.

When a capacitor is charging where is the source of or where are the electrons coming from that deposit themselves on the capacitor surface on the positive end.  Do they come from the battery or are inside the wire?


texts: Can I test a USB port with a multimeter?

texts:
After a recent thunderstorm (Derecho), we had a power outage. After power restored, I noticed my desktop's USB ports (and a PS/2 port) were not responding, even at a BIOS level. Tried a known good keyboard, not plugged in at the time. Still nothing. I'm thinking the USB ports are shot, but I want to test them.

I have a USB cable and a multimeter. I've stripped the cable and found hot and ground (orange and black). My only question is, how do I connect it to the multimeter? I have one of these cheaper ones, not sure how good it is. I've never used one before, and the manual doesn't make sense to me.

Here's the link to more details of my multimeter.


texts: Weird RC time constants for possible debouncing

texts:
I am modifying a CTK-450 keyboard (manufactured by CASIO) into a MIDI controller. Going over the schematics, I found the way the keyboard CPU reads the keystates, which is rather simple. They are arranged in a matrix, which has 11 output scan lines (it really has some more, but those are for other buttons on the keyboard) and 6 input lines (again, they are really 8, but only 6 are useful in this case).

KO0 - KO10 are the output scan lines and KI2-KI7 are the inputs from the keys. The keys themselves are in a button matrix with diodes.

My question is about the debouncing RC time constants used in the circuit, if the RC circuits are even debouncing and not filtering some RF.

It is my understanding that the output side has RC circuits with time constant to=1µs, and the input side has time constants of ti=0.1µs. Are these plausible debounce times for normal key switches? I believe they are way too short to be, and if they were debouncing, I still can't explain why the output side would even have to be debounced, and with a 10x larger time constant than the input side at that.

If these RC circuits are not debouncing, what could they be doing? Some RF filtering maybe? What could they be filtering at the 1MHz-10MHz range? I've looked up what's broadcast in that range, and there seems to only be shortwave radio, including ham radio, but I don't believe the interference would be so big as to warrant adding a filter to the circuit in the first place.

What are these RC circuits doing, and what could explain the odd time constants?

Also, if the RC circuits are not debouncing, could it be the CPU performing that task? This is an open question I have, as I have to modify the circuit through an Arduino in the future, and would like to know more or less how the keyboard is doing its thing.


texts: Common mode noise rejection and grounding instrument current transformer

texts:
Suppose we have a signal from a current transformer over a pair of transmission lines. In order to prevent the voltage between the terminations of either of the transmission lines and ground from floating, we need to ground at least one of them somewhere. If we just directly ground one transmission line and then measure voltage between ground and the ungrounded side, will there be negative implications for measurement of common mode noise on both transmission lines? Is it more desirable to, e.g. reference both lines to ground through equal resistance resistors (of course they cannot both be shorted)?
I feel that the answer is no but I'm trying to build a "precise" instrument and I've never studied how to analyze noise in transmission lines, so I'm not confident.


texts: Does Wifi signal strength affect link speed?

texts:
If Windows says my signal strength is poor, is my bit-rate lower than if Windows says the signal strength is excellent? I have poor signal strength and I have:

1) raised my access point to clear obstacles
2) Made sure the transmitting and receiver antennas are vertical so polarization is optimized

I suppose my next step is buying a longer antenna with higher dbi or dbd. I could also find the access point manual and see if the antenna is somewhat directional and orient to my receiving antenna.

But if poor signal strength does not affect my bit rate, I should probably be ok.


texts: Would a strong magnet have any effect whatsoever on a thumb drive (I'm assuming not) or on an SD card?  It seems unlikely, but I'm hoping someone can give me a definitive answer, since I'd rather not find out the hard way that it actually can.  Assume the magnets are powerful industrial magnets, if that makes a significant difference to the answer.


texts:
I just made a simple voltage follower using TL082. I applied 2.5V to voltage divider 100k and 25k, and apply that 500mV to positive input of TL082. But the output of follower is around supply voltage. The supply voltage is 5V-0V.
Do you have any idea about that?


texts: Capacative proximity sensors - affected by heat?

texts:
I installed a capacative proximity sensor on mt 3D printer to auto level the bed. I've noticed some inconsistencies in how it reads and was wondering if it is/can be affected by heat?

The print bed is heated, and I noticed that it will sometimes fail to read the bed before the safety rocker limit switch activates. I've also noticed that if I leave the heat bed on, with the sensor close to it for an extended period (thus, the tip of the sensor heats up sitting a few MM from the bed).

Is it the heat that is causing these flucuations in readings, or is it more likely the sensor itself not being high quality and just flucuating in it's readings?

I don't want to bother working out a heat-related solution if it's likely not the heat.

The sensor I'm using is this one: http://smile.amazon.com/uxcell-1-10mm-Capacitance-Proximity-Sensor/dp/B00542U3M4?ie=UTF8&keywords=capacitive%20proximity&qid=1462033236&ref_=sr_1_1&sr=8-1


texts:
What is the difference between thermal fuse and MOV and polyfuse.Which is faster and also which companies produce polyfuse, especially in Asia.

I have to search for a component that can save my circuit which is connected via  a TRIAC to a submersible motor. In it may happen that the live and gnd wires may touch due to rupturing of the overhead seal. This would send a surge that cant be handled by TRIAC. A fast fuse is a temporary solution which has to be changed everytime, so i wanted to ask if Polyfuse was viable in its place.


texts:
IT guy here - I have a device called a WattBox in one of my networks so I can remotely cycle power on an outlet.  It also provides me with alerts when something falls outside set parameters.

I've been getting amperage spike warnings from it - normal draw is ~3.2A, and it'll spike up to 20.6A for ~10s, and I'm not sure why.

All of the equipment plugged into it is configured to alert me if something goes wrong; I've confirmed that nothing's power cycling or otherwise functioning abnormally.  The WattBox doesn't give me per-outlet power consumption readings.

The WattBox is fed by an APC UPS rated for 1000W/1500VA load and 12A input.  At any given time we're sitting around 40% load on the UPS.

The WattBox support rep suggested I get the outlet tested by an electrician and also that the power spikes are 'coming from the UPS,' which seems unlikely to me.

My understanding is that you can mess with voltage all you want on the source and that might mess things up, but that amperage is based on draw, on the side of the receiver.  In other words, you can't "send" more power than something draws; there has to be a vacuum to fill.  So, an amperage spike would represent a device pulling more power.  The exception being if you hike up the voltage enough, it would "push" so hard that something breaks, and then yes, you've got an open gate for energy to flow through.

Is my understanding incorrect, and is it possible that the UPS is actually at fault here?

My concern is that the issue is the WattBox itself. All of the most critical network gear is plugged in to it, so it represents a single point of failure.

Part of why I don't think it's any of my network gear is because these amperage spikes happen during off-hours when everything should be as idle as possible, and also because I'm not seeing any alerts, errors, or odd behaviour showing up in logs at the times I'm receiving the amperage notifications.

And, with something that's difficult to reproduce like this issue, how would one go about isolating it down to a specific WattBox outlet if it is my network gear?


texts: Ethernet Port Listener Throughput Maximisation

texts:
We have a distributed sensor network (12 nodes), using Ethernet as the backend protocol. These are networked at 100Mb/s to a single 1Gb/s link using a 16-port switch.

I've previously seen Java and C code to listen to a port. However our aim is to get data into the hard drive ASAP. The nodes will be transmitting with >50% network utilization meaning the Gb/s link will have a very high utilization. The data throughput will be too high to put into local RAM without issues write-read management.

My question is, what issues do I need to access when piping data as fast as possible to a hard drive. We are a single remit, that of real time data acquisition. Therefore filling RAM and later dump to HD with a gap in data acquisition is unacceptable.

Thanks.


texts:
Recently I've attempted to use an oscilloscope to analyze directly the output of a bridge rectifier and I've learned that this is impossible and dangerous unless using an isolation transformer. Also, along the way, I've learned many other things thanks to the wonderful help and support received on this site.
But I've an other question: Could I have any issue powering a circuit by means of a linear power supply (that internally has a transformer) directly connected to the AC mains power (TT system in Italy) and connecting the oscilloscope's probe to the same circuit?
In other words: Has any linear power supply intrinsically got isolated outputs or do I need to search for a particular linear power supply?


texts:
I have a NI DAQ and while connecting wires I tightened the screws a bit more. When I tried to unscrew, the screw head broke and came off. Now I am unable to remove the screws and use the particular pin.

Could anyone suggest how I can remove the broken head screws?


texts: Amplifiers: IC selection and determining its correct values

texts:
I am onto learning and building electronics, and as a start I decided to build audio amplifiers. But of late the search for a good IC is becoming tough as there is an overwhelming amount of options.

So what is the general rule of thumb a pro follows when they do the search?

I also came across some resources, RaneNote - Audio Specifications and Understanding Amplifier Power Specifications from rayfes.com, that highlighted what needs to be the correct value any datasheet should show. If true, how to find out their values from the datasheet itself?

For eg, this IC MAX9709 does not specify the measured bandwidth of THD+N (if I am looking correctly). So how can I find out?

UPDATE
PS: i was searching for
- Class d
- Input power - 12V
- Bluetooth, USB
- Output power(RMS) - 80W
- Efficiency > 90%
- Total Harmonic Distortion(THD) <1%
- Signal to Noise Ratio(SNR) > 90dB
- Frequency Response - 3dB from 20Hz to 20kHz

So even after such considerations, there is surely some other factors a designers look for apart from cost. How do they make it easy for themselves.


texts: Searching for standalone unix development board to connect DC motors

texts:
I though a bit about the board and came to the conclusion that it may be more intelligent to use a stand-alone component which provides serial ports and an unix os which I then can control over the network. I want to write the port driver myself so it shouldn't require to implement a big sub protocol like I have to do with USB and similar.

Which board is recommended for such a task?

I found so far:

gooseberry
beagleBoneBlack (does this require a host?)
cuubieboard
else?

they mostly support the arm branch of FreeBSD as fallback archlinuxarm is there too

Is there a better port then the old serial one?


texts: PCB female jack and power supply male melted

texts:
I've been working in my thesis project which consist on a PID controler to mantain a certain temperature in a case. The heater module is made of two 40W-12V 3D printer resistors and one 15W-10 Ohm wirewound resistor. In addition to these, I have an Arduino Uno, a 20x4 LCD screen, two temperature sensors and two PC coolers (2W each) which all sum up in 5W (rounding up). I'm using a 12V-10A switching power supply.

When the PID is at 100% the tension in the resistor (Rparallel= 1.5 Ohm) is supposed to be 12V, but due to the cables and transistor (IRF540N) drop, the maximum tension is 10V. So, all in all, in maximum behaviour I would be drawing 66.6 W + 5W= 71.6W.

The PID circuit is as follows:

The female jack that is soldered to the PCB is:

which is located near decoupling capacitors in the PCB:

The problem:

I've been doing some test to set up the PID's parameters for over a month (more than 40 hours of tests) without any problems. Suddenly last week while doing a test I smelled like something was melting and found this:

The power supply still works well so I wouldn't say there was an overdraw of current. My best guess would be that the PCB jack couldn't handle that much power but then, why did it resist more than 40 hours of testing? Something had to go wrong this time?

I need to know the cause of the problem so I can continue with the tests. Obviously I will replace both conectors and try to find a more robust one for the PCB but if the problem comes from the power supply or the PCB circuit itself i will face the same issue again. What would you say the problem was? Could the power supply suffered an overdraw and still be working? Is there a way to determine which component overheated first (the PCB jack or the power supply conector)?
Would you recommend to solder the power supply directly to the PCB?


texts: Smooth and no-flickering dimmable light source

texts:
My goal is to record a video with a varying intensity light source.

No flickering at any frame rate (frame rate 30 60 120 240) while watching frame by frame, not human eye.
Smooth dim level
Any type of lamp is OK. (DC powered is preferred)
Dimming by voltage controlling from signal generator (sine shape about 10-60 Hz or higher)

Many requirements make me confuse how to choose the right things to the right job.

I tried dimmable halogen capsule with 12VDC. It worked well when I powered it using large DC power supply. Varying voltage changes light intensity as I need and cause no flickering. But when I use the signal generator to smoothly dim the light, it cannot afford that high current.

I will try LED with 0-10V dimmable driver. No need high power source. But the price is expensive for me. I want someone to make sure it will be the right way or not? I am worried about flickering at high frame rate.

Could you please recommend the type of light source, driver (if needed)? Or I have to go back to halogen lamp and find high power oscillator?


texts: Voltage on the grounded conductive devices when plugging in non-grounded outlet

texts:
Most outlets in my house are non-grounded (line and neutral contacts only). I just bought a Hakko fx-888d soldering station, and immediately noticed that touching the iron-station cable gives the same sensation as when I plug in my aluminium Macbook.  This sensation disappears when I unplug both devices. I measured the voltage between the ground (from a grounded outlet in the bathroom) and the Hakko cable; it was about 100...110 V (I used the AC regime of the multimeter).

What causes this voltage? Is it dangerous for me or for electronics?

UPDATE: I live in the Netherlands, where having 2 contact outlet is allowed. The human safety is ensured by RCD = GFCI. The house is not that old and is well wired (with copper) and grounded, where required. While I'd be happy to improve it and rewire the ungrounded outlets, it doesn't make much sense as I am renting.

Also, plug orientation here is arbitrary (plug can be inserted in the outlet in two ways), so the design never relies on which wire is neutral and which one is line.


texts: Can I connect a single color LED string to a RGB DMX512 controller?

texts:
I am planning on doing a bit of a light show this christmas on my house, I have ordered a bunch of 5050 RGB LED Strings, DMX controller, DMX Bridge and will be running the show using Vixen software.

Now, I already have some single color (2 pin) LED strings and I would like to use these too to make things like Stars, Mini Trees etc. Is it possible to connect a 2 pin string to a RGB controller? I am presuming I would simple hook one wire (Ground) to the V+ connection on the controller and the positive wire to any of the R, G, or B connections on the controller?

Hopefully someone can give me some insight into this as I am in the planning process, and want to be able to set up the sequence as soon as I can so I can test it out when my Bridge and Controller arrive in a few weeks, and hopefully be able to include the single color 2 pin LEDs in it.


texts: Current Bluetooth devices are supposed to have frequency hopping technology built into them.  However, my Oontz speakers skip when I use the apartment complex WiFi.  Most likely, it is because they are using the same frequency.  Are there any devices that can be used in conjunction with my laptop and/or speakers, that can adjust the Bluetooth channel of the speakers?


texts: Digital potentiometer - different voltage

texts:
What would be the "correct" way to replace an analogue potentiometer with a microcontroller controlled digitalpotentiometer, when the require voltage is higher than what the chip can support?

In more detail: If I want to replace an analogue potentiometer for a 10 Vdc signal line with a digital potentiometer that only supports up to about 5 Vdc, what is the best way to achieve this ?

Is it a simple 5Vdc digital potentiometer with an opamp before/after to adjust the voltage accordingly ? Or...?

Please be specific - circuit diagrams for achieving this will be appreiciated. Basically, replace a basic manual potentiometer with a digital one, for a different voltage level.


texts:
I have been doing some net-surfing on Farnell's website and stumbled upon a section called

  MELF Surface Mount Resistors

According to Wikipedia, this package family has a rather funnily sounding de-abbreviation Most End up Lying on the Floor, since they are extremely easy to lose. This may be due to the fact that they are cylindrical... I myself have lost quite a few of such diodes.

Wiki says, that there are three basic sizes. MELF, MiniMELF, MicroMelf - the two latter are in the power-rating range of 0603/0805 resistors. The 1W MELF package is obviously useful for dissipation reasons.

So my question is, why on Earth would anybody design a board containing small MELF components, since they can easily be replaced with more modern flat parts? I cannot see a single advantage. Please prove me wrong.


texts: Does dividing a clock increase its jitter?

texts:
I want to have my microcontroller and ADC using a clock derived from the same source in an effort to avoid intermodulation effects. All clocks are under 50 MHz.
The maximum SNR out of an ADC is bounded by the jitter of its sampling clock. This means that I want to make sure to keep the jitter of the sampling clock below some threshold.
Does anyone have some information on a good way to handle this, or some information about gotchas? I looked at some of the fancy clock/divider ICs, but they are overkill in price, power, and frequency.
So far I've thought about two methods.

Use external ICs like flipflops to divide down the clock.
Use the timers/counters in the MCU to divide down the clock and output it to the ADC.

I tried to find some information about how much a clock will degrade when passed through flipflops or MCU timers/counters, but I couldn't find any information.


texts: Toggling a high-power relay with a Microcontroller

texts:
I've got some relays connected to some 230V high-current spotlights.
I would like to control 16 of these with a microcontroller.
I'm thinking of creating my own PCB.

  I have checked the datasheet, it's the 22.32.0.024.4520
  (http://datasheet.octopart.com/22.32.0.024.4520-Finder-datasheet-10127161.pdf)
  but I can't really find the required voltage or amperage to switch on
  this relay.

    Peter Bennet: 91 mA (24 volt at 2.2 Watts)

I'm thinking of connecting it like this:

simulate this circuit – Schematic created using CircuitLab

Using another relay isn't really an option, since I've got them in stock and they work for the spotlights I have.

  I'm not a 100% sure if the diode is necessary. The component names
  also aren't final.

    Richard Crowley: Protection of reverse voltage generated by the collapsing magnetic field. You might want a 1N4002 or higher for that.

Would this application provide enough "protection" for the microcontroller? I don't see how the 24V is a problem to the microcontroller (and other devices connected) but it might just be?


texts:
I am using an MLX90632 (MLX90632-S-LD-BCB-000) infrared temperature sensor to build an application which reads an object's temperature among other things.
MLX90632 manual

The MLX90632 comes with a default refresh rate of 2 Hz which is unacceptably low for my application.
Supposedly, the sensor has configurable refresh rate, which is configured by writing specific values at 2 specific memory addresses in its eeprom memory.

The datasheet says that the eeprom should be unlocked with a command, the specific memory positions should be erased by writing 0x0000 to them and then the eeprom should be unlocked again and write the actual values.

I had written the program below to do this task but it does not seem to work, when i read the sensor's refresh rate,after changing it, it has the default rate (eeprom contents not changed).

I have also seen Sparkfun's driver which has the same implementation as mine and they have put a comment there:

  Requires unlocking the EEPROM, writing 0x0000, unlocking again, then
  writing value.
  The datasheet doesn't go a good job of explaining how
  writing to EEPROM works.
  This should work but doesn't. It seems the
  IC is very sensitive to I2C traffic while
  the sensor is recording
  the new EEPROM.

For this reason instead of polling the sensor to check its eeprom_busy bit i just put a delay, long enough for the memory operation to finish before trying anything else. Still does not work.

I wonder if anyone has managed to write new values to this sensor's eeprom memory and how they managed it.
Is there anything wrong with the logic in my implementation?

Note: The program sends what it is supposed to send via i2c to the sensor - this has been checked with a logic analyzer - I am just looking for errors in the process

int main (void){

    // initialize mcu code etc...
    // ...
    // ...

    rate = mlx90632_get_refresh_rate();  //the rate we get here is 2Hz
    mlx90632_set_refresh_rate_1Hz  ();  //write the new refresh rate to sensor's eeprom

    // mlx90632_reset();   // a reset won't help here either

    rate = mlx90632_get_refresh_rate();  //after changing the rate, still gets 2 Hz refresh rate

}

/*-------------------------------------------------------------------------*/

// function to set the refresh rate to 1 Hz
int32_t mlx90632_set_refresh_rate_1Hz  ( void ){

    uint32_t meas;

    meas = 0x810D811D;  //value supposed to be written to configure the 1Hz refresh rate

    // put to sleep mode before writing to eeprom
    mlx90632_mode_type previous_mode = mlx90632_get_mode();
    if (previous_mode == continuous_mode)
                mlx90632_set_mode(sleep_step_mode);

    //EE_MEAS_1 and EE_MEAS_2 are two 16-bit registers, needed to be written for the configuration
    //  EE_MEAS_2 is right after EE_MEAS_1. We write the incrementally as one 32-bit register
    if ( mlx90632_write_eeprom32( EE_MEAS_1, meas ) < 0 )
        return -1;

    // return to previous mode
    mlx90632_set_mode(previous_mode);

}

/*-------------------------------------------------------------------------*/

int32_t mlx90632_write_eeprom32( uint16_t address, uint32_t value ){

    while( mlx90632_eeprom_busy() ){;}    //wait until sensor is free

    if ( mlx90632_unlock_eeprom() < 0 )     // unlock eeprom for writing
            return -1;

    // erase eeprom register before writing
    if ( mlx90632_write_reg32(address, 0x0000) < 0 ) return -1;     //write a 32 bit value to the eeprom starting from  "address"
        nrf_delay_ms(500);
        //while( mlx90632_eeprom_busy() ){;}

    if ( mlx90632_unlock_eeprom() < 0 )
            return -1;

    // actually write the desired value
    if ( mlx90632_write_reg32(address, value) < 0 ) return -1;
            nrf_delay_ms(500);
            //while( mlx90632_eeprom_busy() ){;}    // to do: add timeout?

    return 0;
}

/*-------------------------------------------------------------------------*/


texts:
I have an older NI DAQ (PCI-6251) which comes equip with a bunch of ADC's, two DAC's and a hand full of DIO ports.  I need to output a pulse of variable width, amplitude and DC offset which the DAQ can do but once you fall below about 5us pulses the rise and fall times become a considerable amount of the actual pulse.  For example, I would like to idle the DAC at 5V and then have it pulse to 0.5V for 1us and return to 5V without having the pulse be too distorted.

Is there a simple circuit that could sharpen the edges of the pulse while still allowing me to keep a DC offset?

My first thought was to use a P-TYPE MOSFET in a pull-up configuration with the gate tied to a Digital Output signal but then I wouldn't be able to use just any DC offset or pulse amplitude.  The rise/fall times of a Schmitt trigger would be perfect but I'm not sure how I could use the digital output in an analog signal.

Let me know if there is more information I can provide. Any help would be very much appreciated!


texts: Question on timing diagram of a SR Latch with different gate delays

texts:
Below is the verilog code that I wrote to implement a simple SR Latch. Note that I assumed different gate delays for the same NOR gate. (#10, #5)
module rs_latch(
   input S,
   input R,
   output Q,
     output Q_L
        );

    assign #10 Q_L = ~(S | Q);
    assign #5 Q = ~(R | Q_L);

endmodule

I expected Q and Q_L would oscillate right after 500ns, when both S and R are changed to 0. When the gate delays were the same #5, they did oscillate. However, in this case, as you can see from the image below, it is not oscillating.

Below is a hand-drawn diagram that I had expected to appear.

Could you please explain why it is not oscillating?


texts: Calculating input impedance in a simple circuit

texts:
I want to calculate the input impedance in the following circuit:

simulate this circuit – Schematic created using CircuitLab

From the leftmost loop I have that

$$U_{in}+I_{in}R=V_1$$

so it seems like I need to express V1 in terms of Uin, but I am unable to do that. How should I approach this problem?

Can I replace the driven current source with an equivalent voltage source in series with the resistor? And then add the two voltage sources which would then be in series?


texts: what IDE and software can I use to program a microcontroller

texts:
I am aware this sounds like a dumb question, but I'm really unsure what IDE / Software I could use to programme microcontrollers.

I have a background in C++, but I never got to the part where we programmed microcontrollers during my education, so that is why I'm asking here.

As an IDE, of course any text editor would do if you know your way around programming languages, but some IntelliSense for C would be nice to have. I currently use VS2013 on a daily basis, but maybe there is some software that can be used as an IDE and can be used to compile code and flash on the microcontroller (I have never tried it, but I'm pretty sure VS cannot do it).

I have seen many modules that are sold with firmware that requires you to learn their own language (like BGScript for the BLE1xx modules, or the Arduino boards), but I really do not want to learn a new language.

I will try to programme the nRF51822 microcontroller from Nordic Semiconductor and I have read some posts that lead to IAR Embedded Workbench which it's pretty expensive for a beginner like me. I've also heard something about Keil, yet I'm really not sure what to do since my knowledge of this field is far to low.

I would appreciate some pointers on where to find my answers if this question is to general or to localised or it doesn't make any sense.

EDIT: What are your thoughts on AppCode by JetBrains, some guy seemed to have created C / C++ compilers and IntelliSense support for it here ?


texts: I'm looking inside an Inform brand UPS. On its communication board there are 6 chips. Four optocouplers, one NE555 timer and a mistery IC, pictured below. The communication board only has the USB-B populated, the DB-9 footprint is unused. On the mistery chip, I can make out the "RICHC" brand and four other strings: "RC-USB0100147", "1533N" and "BTS158E2". None of the strings allowed google to give me any hint about which company made it and what exactly this chip does (datasheet or at least some marketing brochure). Can you help?


texts: How ADSL Demodulates (restores the order) the signal for dummies

texts:
I am not an electric engineer so sorry for questions that might miss some fundamentals.

I am trying to understand the ADSL modem. The ADSL modem sends the data over different frequencies in parallel. However I have learned that faster frequencies means higher data rate. So I assume the data is transferred over the "bins" with different speed.

Which algorithm exactly is deployed to ensure that data is restored in the correct order? The link with simple explanation will be fine.

UPD: As smart people mentioned, I didn't meant actual speed of signal but bitrate per channel.


texts: Use network cable internal wires for Arduino project connections

texts:
I am new to Arduino and Raspberry Pi, and I have no eletronics knowledge outside of this. I have a good programming background.

I just learned how to solder (basic), got my LCD working, my rain sensor, external temperature sensor, barometric sensor and camera working. They are connected and logging data.

Now I want to put this thing outside. I'll need long wires for my rain sensor and temperature sensor. Can I dismantle a network cable (Furukawa Cat 6) and use the pairs inside?

I'll need two wires for the rain sensor and three for the temperature sensor. One network cable has more than enough pairs, so I'll just need to pass one cable.

I plan to dismantle both ends and solder.

Is this okay? What is the maximum distance?

The distance would be about 20 meters.

The protocols and interface - I don't know, but I'll look into the datasheets. The barometric pressure sensor is Bmp180, the temperature sensor is the DS18B20 and the rain sensor is the YL-83.


texts:
is i(t)=5 cos(10t+40°) A.
A resistor 4 ohm is parallel with an inductor 0.2H.

ZL=j2

Z= 4 || j2

How do i calculate this?


texts: Driving LCDs with parallel LEDs in singles

texts: I am implementing a LED driver for a LCD that has the particular arrangement of the backlight LEDs shown in the picture bellow, 4 parallel LEDs. It seems quite inconvenient not to have them in a series string as the typical voltage needed over the string is now only 3V, bellow what a typical boost constant current LED driver implementation can achieve with standard 3.3V input voltage. Is there an common appropriate way to do this that enables PWM dimming ?


texts:
I have bought a PIC16F877A microcontroller and its board before and since then,  I haven't used it much because I don't really have enough time and patience to learn C. I was thinking to buy a Netduino since it can be programmed using VB.NET (which obviously I'm familiar with). However, I  didn't want to abandon the stuff I bought earlier, so therefore I'm asking if there is a way to program the PIC16F877A using VB.NET, maybe using the SDK provided in the Netduino website?

Thanks in advance.


texts:
I want to communicate simple requests and ids over ultrasound.
To do this I need to modulate a message onto a 40kHz carrier to drive a ultrasound transducer.
Here you can find a simulation of what I am trying with a gilbert cell for modulation a difference amplifier as a driver for the transducer (not shown in the simulation) and an OOK demodulator consisting of a LP, an average detector and a comparator.

Is the difference amplifier (with +-50V as supply) sufficient as a driver for the
transducer and can I also use it for the other end to amplify
the received signal ?
If it is sufficient which HiV op amp would you recommend ?
Do you see any other design flaws ?


texts:
I'm trying to hack an optical mouse sensor: PAW3204DB. Here is the datasheet. It has a voltage regulator, and I have no idea how to wire this to my arduino. I looked at a different hack for an optical mouse sensor, but the wiring does not include a voltage regulator.

Does VDDA, pin 8 on the PAW3204WB, have to be wired to power? Which would mean:

Pin 6 to Arduino GND
Pin 7 to Arduino +5V
Pin 8 to Arduino +5V
2 Serial pins to 2 other Arduino pins


texts: Why does this schottky diode have three pins

texts:
I'm just wondering why this schottky diode have three pins?

I know two of the pins acts like rectifier but what does the a third pin do?

Source:

http://www.digikey.com/product-detail/en/DB3J208K0L/DB3J208K0LTR-ND/2295704


texts: Isolation and Amplification Circuit for reading multiple analog voltages

texts:
I'm designing a device that needs to take a wide range of analog readings and I'm trying to keep it to one microcontroller with multiple input ADCs. I need to measure voltages between 0 and 12V as well as currents. I also need to measure the voltage drop over a P-Channel high side FET with precision (it should be somewhere around 150mV).

I know I could measure the upper and lower voltages and subtract them but the tolerances on the resistors would not provide accurate enough results.

I'm wondering if there is a way to isolate the voltage differential and amplify it with respect to ground?


texts:
I'm using a Raspberry Pi in a circuit I'm building that includes a few elements.

Elements in the circuit:

PWM driver to control 3 servos
Mic board for recording
Class D Amplifier that drives 2x3W 4ohm speakers
4inch HDMI screen

Limitations:

I can use only one power source plugged into the wall to power the whole system. I'm currently using a 5V 10A power supply.
The enclosure is very small so adding space consuming components can be challenging.

Problems:

Driving the servos causes the low voltage indicator to show up on the pi. The power supply is rated for 5V 10A and the peak current draw is ~3A.
The amplifier is picking up noise from the circuit causing an audible hiss/crackle from the speakers.

Things I've tried:

I tried adding large decoupling capacitors - 1000uf/4700uf right at the Pi's power and at entry point of power supply. The Pi is powered from it's GPIO pins. No difference.
Added additional decoupling capacitors in values ranging from 0.1uf to 10uf right before the amplifier. No improvement.
I measured the voltage at the Pi using a multimeter and it never drops below 5.1V even when the servos are being driven, so why the low voltage indicator?
The noise in the circuit isn't caused by the servos. When I remove the servos there is still noise being picked up by the amplifier. Similarly removing the amplifier doesn't help get rid of the low voltage indicator while servos are running.

Things that worked:

The only thing that works is powering the Pi from a different 5V supply and sharing common ground. This gets rid of any noise from the speakers and the low voltage warning. However due to Limitation #1 this is not feasible.

Things I've thought about:

Pairing a higher voltage power supply(12v,24v) with a buck regulator to create 2 +5V rails.Use one rail for Pi and one for servos/audio. Not sure if this is even possible or how it would be done?
Finding a power supply which has two +5V outputs. No luck finding one yet. Also seems overkill.

Image of the circuit

What can I do to reduce noise in the circuit to get rid off the low voltage warning and speaker noise?


texts: Leading power factor for residential customers

texts: I'm doing some modeling of LV networks, using meter data (AMI) giving me instantaneous values for real and reactive power, in 5-minute intervals. I am seeing a lot of negative reactive power, which I am interpreting as indicating leading power factor. This is not what I expected to see. This is happening on residential customers without solar. Has anyone done some investigation into typical power factor in an urban setting for residential customers, with and without solar, over a typical day?


texts: Can I use 2uF or 10uF capacitor instead of a 1uF with the LP2951 voltage regulator?

texts:
I want to learn to program and use microcontrollers, and therefore I'm setting up a small power supply. The voltage regulator I've selected says I need a 1uF capacitor at the input pin.

So my question is, is this the exact value I need or is it the minimum? Can I use a 2uF or even a 10uF capacitor instead?

I'm planning on using a 9V battery as the power source.

EDIT:

The voltage regulator is the LP2951.
See page 15 and down.

However, I've been looking around a little more, and I wondered if I can use this regulator instead? http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=156827308&uq=635456207616008876

Does it matter that its 800 mA instead of 100 mA on the Texas Instruments Regulator?


texts:
My original ST-LINK/V2 has been broken. There was the Short circuit between VDD and GND pins. I changed the MCU(STM32F103C8T6) and the voltage regulator(LD3985M33R) with new ones. Short Circuit problem gone, but when I plugged ST-LINK to USB port, the indicator LED is on very lightly. USB Device not recognized window shown at PC screen.
I measured VDD pin as 3.29V. Power is OK.
ST-LINK/V2 is not open source and I couldnt reach its schematic.
What should I do to fix the issue? Thanks your helps...


texts: Is resistor on LED's necessary after voltage drop?

texts: Let's say we have perfect 5V DC 0.1A power supply. Obviously for one LED we would need a resistor (I'm well aware of Ohm's law), BUT what if we connect bunch of LED's in series. And the current drain is well above the power supply, so voltage on those LED's drops to 2.5-3V. Would you still need to add resistor if LED's voltage is about 3.2V? It might be a silly question, but I thought it'd be cool to not have a resistor in such case (because LED's would be brighter that way) and better ask and be sure than be sorry, right!? Thank you in advance!


texts: Does driving a speaker with a DC offset AC signal matter?

texts:
Do these two input signals have different effects on a speaker?

An AC signal with some value of DC offset.
Same AC signal but centered at 0 V.


texts: High Speed Piezoactuator Driver-Unexpected (Low) Voltage Output

texts:
I'm working on a project that requires charging and discharging a piezoactuator (150V, 1.5μF) extremely fast, IE total slew time allowed ~50μs (so somewhere around a 11A pulse). My background is in materials science, so after a lot of stumbling around in the dark I've wound up with the following circuit based on what I have available for now:

I forgot to relabel X4-A and X5-A, they are STGP19NC60HD IGBTs, and Vcc/Vee for TL082 is +/- 18V.

Essentially a function generator provides a +/- 10V square wave, where at +10V optocoupler 1 (OC1) turns on and subsequently turns on IGBT X4-A, which allows the piezo to charge, as IGBT X5-A is off. When the square wave inverts to -10V OC1 and X4-A turn off, TL082 inverts the -10V, turns on OC2 and therefore turns on X5-A to discharge the piezo. While I know there are a lot of things with the circuit that probably don't make sense (there are some artifacts left over from a few other inspiration sources), this circuit slews the piezo at the rate set by the RC constant set by R7, as by (mediocre) design. The only problem is the piezo never reaches the voltage that is expected; 150V-voltage drop across IGBT X4-A (~few volts). Instead the voltage applied to the piezo is limited to, and varies directly with the gate voltage (~X4-A Vge - 2V).

I've read through a few other SE posts that seem to have similar problems, but none have passive elements downhill from the emitter, ie the emitter seems to always run straight to ground. I know that there is something very fundamental I'm not understanding about the IGBT's operation but I can't seem to figure it out or find a working circuit to modify. It would be great if there was some tweak to fix the voltage issue, but I wouldn't be surprised if this thing has to be completely scrapped and started from scratch.


texts: Stepping down negative and positive voltage

texts: I have an old device that contains multiple buttons that are all tied to some connectors in the back. The connectors are hooked up to a computer that interprets each button press and sends out a command depending on what button was pressed. When the buttons are depressed, there is a constant 24V DC voltage coming out of the corresponding pin from the connector. When the button is pressed, the voltage on that same pin quickly changes to -24V DC. I am in the process of upgrading the hardware in the computer and the IO modules can only accept a range of 0 to +5V. I am trying to figure out a way that I can step down the +24V down to about +5V and convert the -24V to something close to 0 so that the computer modules can interpret that as a low. Because of the positive and negative voltage toggling through a single wire, I am assuming that I just require a single converter. I am so confused as to how I can even work this out or if it is even possible. Any help would be greatly appreciated.


texts: Read a common digital output from multiple digital inputs

texts:
I'd like to read a single digital output with two separate systems, each of which has a digital input. Both systems have a common ground.

In principle, since the digital output is low-impedance and since digital inputs are high-impedance, can I just tie these two inputs together at the same output without any contention or crosstalk, or must I add in some form of signal conditioning? Does this concept scale? Can I wire N digital inputs together to read a single digital output?

If not, what kind of buffering should I try to implement?

My use-case for this scenario is to wire a quadrature encoder output to both an off-the shelf PID controller and a separate system for logging ticks.

Cheers--and thanks for the..eh input.


texts: Electricity path through a 240V heating element

texts:
My simple understanding of electricity is that you always need a circuit (from + to -, or from hot to neutral), in order for current to flow.

Now, I recently had to fix my water heater (which is running on 240V), and noticed that the heating element basically consists of two hot legs (at 120V each) coming together. There is no neutral, no ground, just two hots (e.g. like this).

How does that work??? Where's the circuit? Why doesn't it just explode? ;)

P.S. I know I have 240V in my house, and that I get it by combining to 120V legs. But what I don't understand is how a heating element can work by just having two hot legs come in; without any neutral to close the circuit.

For those of you who have never seen those heating elements, this is what it looks like: https://imgur.com/ek6Bxeu
Two connectors that basically each receive 120V, with about 10Ω between them.


texts: How can I calculate my output and gain when 2 sources are connected at the positive input of opamp?

texts:
I can't solve this problem because the opamp's positive input has 2 sources.
How can I calculate my output and gain when 2 sources are connected at the positive input of the opamp?


texts: What are the differences between \$I_B\$, \$I_b\$, \$i_B\$ and \$i_b\$ in a transistor?

texts: It is quite confusing when I do some calculation with \$I_B\$, \$I_b\$, \$i_B\$ and \$i_b\$. Are they the same? This problem also appears in the current of emitter and the current of collector.


texts: Selecting Capacitor to reduce AC ripple from Car Alternator - LED Indicators only work when Engine Off

texts:
My neighbour has recently installed some aftermarket LED indicators, when the engine is switched off the units work as expected, switching from white headlight mode, to blinking yellow mode.
When the engine is running the units become erratic and do not behave as expected. I suspect interference from the alternator is confusing the LED driver circuit.
What capacitor could I add and where in the circuit to help reduce the noise?
Much Appreciated


texts: Is it possible to edit gerber file using allegro?

texts: I want make some corrections in gerber file. Is it possible using allegro? Or is any other better method to do it?


texts: Is my Kirchoff's rules solution with mixed current and voltage source correct?

texts:
Problem:
Find \$I_{1}, I_{2}, I_{4}, I_{6}\$ using Kirchoff's rule

simulate this circuit – Schematic created using CircuitLab

\$E\$ is the voltage source of 8 Volts and \$I_{general}\$ is the current source of 3 Amps.

My steps:

This is what I got:

I think there are 5 branches and 3 nodes and also 3 independent loops.
So the number of needed equations = \$3-1 = 2\$
Using this I got equations:

For node 1: \$-I_{6}+I_{1}+I_{general}\$

For node 3: \$-I_{4}-I_{1}+I_{2}+I_{6}\$

Also I think there are 2 loops needed for equations: the bottom rectangle and the left one:

Loop1: \$1-3-1\$

Loop2: \$3-2-3\$

So we heave 2 more equations:

1) \$I_{1}R_{1}+I_{6}R_{6}=0\$

2) \$I_{2}R_{2}+I_{4}R_{4}+I_{2}R_{3}=E\$

So we got system of equations to solve:
\begin{cases}
-I_{6}+I_{1}+I_{general}=0 \\
-I_{4}-I_{1}+I_{2}+I_{6}=0 \\
I_{1}R_{1}+I_{6}R_{6}=0 \\
I_{2}R_{2}+I_{4}R_{4}+I_{2}R_{3}=E
\end{cases}

Solving which, gives this result:

$$I_{1}=-2.571\\ I_{2}=-1.244\\ I_{4}=1.755\\ I_{6}=0.42$$

Question:
Is there anything that I did right? I can get 0 in product of sum of I's but for that I need to change some signs a bit. Did I solve this correctly or there is something wrong in it or completely wrong?


texts: How to convert to unsigned long from 4 char array?

texts:
I am programming an AVR chip (atmega1284p) with c code, I am using SPI to read in 4 bytes from a chip on my circuit. I would like to take those 4 bytes and return them as an unsigned long.

I can print the bytes to the serial port and I have received logical values, which I can calculate by hand to get the correct value. I then try to do this with programming and I get very peculiar results. Here is the code snippet.

Note: returnBytes is a 4 character array with the correct character values. Also, I am using a bitmask to make sure that the shift doesn't have anything weird going on -- just incase (works the same with and without bitmask).

unsigned long returnLong = (returnBytes[3]&0xFF)<<24;
returnLong |= (returnBytes[2]&0xFF)<<16;
returnLong |= (returnBytes[1]&0xFF)<<8;
returnLong |= (returnBytes[0]&0xFF);

return returnLong;

What I get from this is peculiar, in that it should be counting from 4.2bil to 0. It starts at around 4.2 bil, generally counts down and then drops to 30,000 after a couple of counts, then jumps back to 4.2bil after a couple of counts. (Yes the counter will wrap back around once it hits 0).

I am certain that the bytes are correct and my method of printing the unsigned long is correct.

Here is the output of this code (First line is bytes 3 2 1 0, Second line is the value of the unsigned long)

255 254 230 157
Counter Value: 4294960797
255 253 206 25
Counter Value: 4294954521
255 252 182 90
Counter Value: 4294948442
255 251 158 153
Counter Value: 4294942361
255 250 134 159
Counter Value: 4294936223
255 249 110 139
Counter Value: 28299
255 248 87 207
Counter Value: 22479
255 247 65 170
Counter Value: 16810

Hopefully this is enough info.


texts: Load sharing device from different power sources

texts:
Is there a circuit or device that can facilitate load sharing of different power supplies? For example, suppose I have a single 100 Watt Load that operates at 12VDC, a 9VDC source capable of delivering 75 Watts, and a 12VDC source capable of delivering 75 Watts. I need help from the 9VDC source to deliver enough power, but the voltage is wrong.

What are some options? I'm not afraid of answers that go outside of the electrical domain (ex: flywheels), but I would prefer a circuits/electronics solution. Is there such a thing as a multiple input, single output SMPS? Can I throw a boost converter on the 9VDC up to 12VDC and then put it in parallel with the 12VDC?


texts: Can I measure a differential voltage signal using two arduino analog pins?

texts: I have a SO2 sensor (CiTiceL 3MS/F) which has differential voltage output. I'd like to read this using the Arduino MEGA 2650. If I use a separate battery for the sensor and the arduino, can I connect the high output to one analog pin, the low output to a second pin, and subtract the voltages?


texts: Why would you use a non-contact voltage detector if you have a multimeter?

texts:
I was reading this Fluke multimeter safety manual and I came across this sentence: http://faculty.riohondo.edu/jfrala/fluke_multimeters_-_abcs_of_multimeter_safety_multimeter_safety_and_you_application_note.pdf

"Non-contact voltage detectors are a quick, inexpensive way to check for
the presence of live voltage on ac circuits, switches and outlets before
working on them."

Question 1: Why exactly is this relevant? If you are going to work on a circuit, why not use your multimeter directly to check the presence of voltage?

I thought about safety but I can't see a real reason. If you are worried about safety, once you measure the presence of voltage with the non-contact voltage detector you would need to use your multimeter next anyway (and the "safety" you supposedly got from measuring it with the the non-contact detector would becomes useless).

What am I missing?

Question 2: Why exactly are these called "non-contact" voltage detectors? You still need to physically insert them into an outlet (or somewhere else you want to check) in order for it to work.


texts: Are there any cases that Source Transformation method can not be applied?

texts:
When I tried to use Source Transformation method on the 12 V voltage source the problem gave me a wrong answer. If I transformed the 2 A current source it works just fine. My question here, Is there any Cases in Deducing Norton and Thevenin equivalents where I cannot use source transformation method?

The right answer for I Norton is -0.4 A


texts: I know there are lot of examples are given on internet. I have searched and I found good one. I am not professional in electronics engineering. I am Software Developer and I am trying to create a module that converts 12v into 5v. Actually I want to charge my usb device(mobile/mp3 player) from my motor cycle battery. I have found good tutorial on electroschematics site. but, I am confused in selecting capacitor for C1 and C2 defined in diagram. I dont know what is the voltage for those capacitor?


texts: I2S audio interface - sync of MCLK and LRCLK signals

texts:
I plan to use IC AK4430, an I2S digital interface sound output chip, to be connecte to an ESP-07 Wifi module via 3 wires (BITclk, LRclk and DATA). But the IC also require an input signal that they call as MCLK (master clock).
AK4430 on Digikey: https://www.digikey.com/product-detail/en/AK4430ET/974-1017-1-ND/2333403/?itemSeq=329224867
AK4430 HTML datasheet: https://www.digikey.com/htmldatasheets/production/755129/0/0/1/ak4430.html
Page 9 of datasheet shows this:
The external clocks required to operate the AK4430 are MCLK, LRCK, and BICK. The master clock (MCLK) should be
synchronized with LRCK, but the phase is not critical. The MCLK is used to operate the digital interpolation filter and the
delta-sigma modulator. Sampling speed and MCLK frequency are detected automatically, and then the internal master
clock is set to the appropriate frequency (Table 1).
The AK4430 is automatically placed in power saving mode when MCLK, LRCK and BICK stop during normal operation
mode, and the analog output goes to 0V(typ). When MCLK, LRCK and BICK are input again, the AK4430 is powered
up. After exiting reset following power-up, the AK4430 is not fully operational until MCLK, LRCK and BICK are input.
And also shows the following table also at page 9:

From the table, if I pick freqSampling/fs = 44.1 Khz and MCLK = 512*fs, then MCLK would be 22.5792 Mhz.
That 22.5792Mhz SMD 4-pin oscillator could be used: https://www.digikey.com/product-detail/en/KC2520Z22.5792C1KX00/1253-KC2520Z22.5792C1KX00CT-ND/11610678/?itemSeq=329226141
The question is that the text above (shown on page 9) states that "The master clock (MCLK) should be synchronized with LRCK". So, how can I achieve such synchronization?
This is the basic schematic of the IC:

Another simple question is about the type of audio amplifier that is required to connect to the analog output... it should be class A, B, AB, H?


texts: What's the road map to become a good programmer of microcontroller?

texts:
I'm kind of new to microcontroller science and programming, but do some small project with ESP 8266 .
I want to create a anti theft reliable system with some sensors like microwave sensors.
Could someone please help me that which methods i should Observe for this project?
I just want a summary of the things i should to observe. Also what's kind of test I should use for this?
I will be very thankful if somebody help me and show a road map to me.


texts: Resistor Tolerance - are measured resistor with the same value but different tolerances the same?

texts:
Probably a real newbie question but I can't seem to find an answer easily...

If I have 2 resistors both 1K but one is a 1% tolerance and the other is 10% and I measure them and they are the same. Let's assume exactly 1k, then are they effectively the same?

Could I use the 10% in a circuit that requires a 1% tolerance (as the actual value is within 1%?)

Or is there some other property Im not aware of?

Thanks


texts:
I designed a closed loop resonant buck converter using voltage mode control and simulated on PSIM. Here is my circuit:-

This gave correct results. Now I want to design an input filter so I simulated on LTSpice. In this circuit I had initially put a pulse voltage source at the Gate of the IRF530 and it was alright. Now I made the same circuit as in PSIM for the voltage feedback, but it is giving very wrong output waveforms.

Here since I used LISN modules I did not ground the converter circuit instead it is all connected to the "n" label which is the eut point of a LISN box. C7 without this feedback was 4.7uF, but here in this circuit I changed it widely but the waveforms were all wrong. I will replace C7 by a damped filter. But first of all I need it to work as per the PSIM circuit before designing filter.
I know the problem lies in the feedback part because when I remove the feedback and put a pulse source, keeping the rest intact including the resonant components, I get perfect ZCS.
Also, if in the circuit in Ltspice (the image of which is attached) I remove the LISN blocks to make it absolutely same as in PSIM circuit, I still get erroneous waveforms.
EDIT 1:-
Here is the circuit without the LISN module, exactly the same as PSIM. Here I replaced the diode and MOSFET as ideal devices, but still not working.


texts: How can I safely get power into an outdoor enclosure from mains without a receptacle?

texts:
I’m building a weather sensor suite for a small privately-owned airport, and I’m wondering how to safely and compliantly get power into one of the enclosures. My concerns are safety and code-compliance (understanding that “legal” does not always mean “safe”). This is in the United States.
This unit is for the wind sensors, which have to be installed 30 feet above ground, away from buildings. The best site for this is an existing lamp post (ours, not public/utility) that has three-wire single-phase AC. There are no power receptacles; there are simply three wires running up the inside of the post from buried conduit.
The electronics in the enclosure are all 5V and 12V DC. The enclosure is fully gasketed and is UL-listed. I drilled holes in the bottom and installed listed, waterproof glands for cable entry.
What’s the best way to get power into the box? Two options I’ve considered are:

Running the hot and neutral AC lines into the enclosure and installing a power supply in there. Didn’t like this idea because I don’t know how to deal with mains power inside my own enclosure.

Purchasing a listed, IP-rated, constant-voltage LED driver designed for permanent connection to mains, and that outputs 12V. Fasten it outside the enclosure, run the DC leads up through one of the glands, and use a DC stepdown converter to create the 5V circuit.

Neither of these address the safety ground. The enclosure is plastic but the frame is metal (aluminum).


texts: Using CooCox as an alternative to Keil MDK-ARM - any limitations?

texts:
A very popular and advertised tool for programming ARM microcontrollers is Keil MDK-ARM. The evaluation version can be downloaded here. However there is a code-size limitation of 32 kB for using the evaluation version of Keil. After some searching I found out that the CooCox IDE is a free alternative to Keil and similar software.

So my question, given that CooCox is absolutely free is... Is CooCox an alternative with no such limitations of code-size, etc.?