texts: VHDL CODE Error (12006): Node instance " " instantiates undefined entity " "

texts:
I am having issue with the following vhdl code.
entity ADDSUBTRACT is
port (A,B: in bit_vector(3 downto 0);
      cont: in bit;
        sum: out bit_vector(3 downto 0);
        co: out bit);
end ADDSUBTRACT;
architecture myarchitecture of ADDSUBTRACT is
component FullAdder
port (a,b,cin: in bit;
      s,cout: out bit);
end component;
signal cio : bit_vector(2 downto 0);
signal xor_out : bit_vector(3 downto 0);
begin
xor_out(0) <= cont xor B(0);
xor_out(1) <= cont xor B(1);
xor_out(2) <= cont xor B(2);
xor_out(3) <= cont xor B(3);
AS0: FullAdder port map (A(0),xor_out(0),cont,sum(0),cio(0));
AS1: FullAdder port map (A(1),xor_out(1),cio(0),sum(1),cio(1));
AS2: FullAdder port map (A(2),xor_out(2),cio(1),sum(2),cio(2));
AS3: FullAdder port map (A(3),xor_out(3),cio(2),sum(3),co);
end myarchitecture;

here I am trying to compile a code to perform addition and subtraction.
the error I got is the following,
Error (12006): Node instance "AS0" instantiates undefined entity "FullAdder". Ensure that required library paths are specified correctly, define the specified entity, or change the instantiation. If this entity represents Intel FPGA or third-party IP, generate the synthesis files for the IP.
The same error I got for labels 'AS1','AS2' and 'AS3'.The entity used as a component has folloing code,
entity FullAdder is
port (a,b,cin: in bit;
      s,cout: out bit);
end FullAdder;

architecture Equations of FullAdder is
begin
s<= a xor b xor cin;
cout<= (a and b) or (cin and a) or (cin and b);
end Equations;


texts: Circuit to charge battery from solar panel

texts:
If I want to charge a battery from a solar panel without using a commercial charger, then the essential problem is to create two voltage-triggered switches. One switch turns current on when the voltage in the battery drops below a certain threshold and the other disconnects the panel when the voltage rises to the "full"/higher threshold.

One advantage of having a system like this is that I can select the threshold voltages, instead of the charger guessing what might be optimal.

What would be the right kind of circuit to solve this problem? Ideally, I would like a system that requires no power to operate, at least when it is charging, because I want the energy to be used to charge the battery, not run the circuit.


texts:
I'm trying to understand what is the logic or mechanism used in 3 way or 4 way switches, in order for all swtches to work so that no matter the position of each switch, the lights go on or off without any other switch affecting the others.

So, are they internally using any logic gate that work connecting each swtich, or is it using any kind of flip flop latch or anything like that?

Sorry for this question that might look stupid, but I am trying to learn electronics by myself and came up with this question.


texts: How to characterize SNR for an amplifier with extreme low input signal?

texts:
Often that the OPAMP has an internal noise of 1uV. If I have an extreme high gain of 10000, the noise will be amplified up to 0.01V.

Then, when I input a very low input signal of 10uV, after amplify 10000 times, it will measure 0.1V at the output.

According to typical SNR equation:

SNR (dB) = 20 * log ( Vsignal / Vnoise) = 20 * log (0.1/0.01) = 20dB

It yields a very low SNR of 20dB.

So, with the above mention, does this mean that my amplifier has a very low SNR characteristic?


texts: Simple circuit to limit current through a FET

texts:
I am looking for a simple circuit which can be used to limit the current flowing through a FET. There is a bus line which is pulled up to the battery voltage (12V) by a 510\$\Omega\$ resistor. A FET pulls the line low to transmit a pulse along the bus. In some cases it may be occur that the bus is directly connected to 12V, in which case the current through the FET needs to be limited.

We would probably use a 2n7002 FET, so the current needs to be limited to below 300mA. It does need to be able to sink up to about 200mAThe FET needs to provide a hard pull down, so adding an inline resistor is not an option.

I looked at using current limiting diodes (such as those from Central Semi) which have the perfect type of characteristic, but the current limit is too low.

What options are there which are simple and have a low component count?


texts: How can I make a DIY clamp sensor for my power meter project?

texts:
My aim is to make a power consumption data logger and analyzer that is non-intrusive and can be hooked anywhere to monitor the power consumption on that line. I've come across clamp sensors which uses the principle of electromagnetic induction to measure the current on the line. These products are usually in the form of a complete meter. For my engineering project, I want to implement this manually by myself. I guess one can make a clamp sensor by winding a wire, but I'm not well versed in the technical details of doing so. How can I build one that is accurate, and how can a design an appropriate amplifier circuit?
The idea is to supply this small secondary current to op-amp circuit, and then use a microcontroller with built-in ADC to measure and calculate the different electrical characteristics.


texts:
I am attempting to drive 3 High-power LED's in parallel and wish to strobe them.  The issue I'm running into is in parallel, the LED's require 3v and 8.4A, however, the 555 timer requires higher input voltages and doesn't output enough amps.  Secondly, I'm researching the use of an MCU but am very new to all this.

Question 1:  Can I overdrive the 555 and it operate, or will it burn up?

Question 2:  Will an MCU be the appropriate solution utilizing only a battery source of 3.7v and 12A?  I only need it to strobe for about 10 seconds and then the circuit shut down.

Thank you


texts: Drive stepper motor with audio amplifier?

texts:
I am as a beginner in electronics contemplating how to build a motor driver for a stepper motor.

From what I have read, the more sophisticated drivers will have a feature known as micro stepping which basically means that instead of switching winding current on and of per phase (full step) or adding a layer by alsow reversing polarity (half step), the voltage is adjusted in levels where up to 8 levels is common.

Further the state of the art with this technology talks of how an even and artifact-free sinusoidal voltage signal is the most important to get a smooth running and efficient motor with high precision movement.

It occurred to me that this resembles the goals of audio equipment as well. So my question is thus: Would it be feasible to use a speaker driver to drive a stepper motor? Why/why not? What are potential caveats that I must be aware of?


texts: Building a better staged 1's complement adder tree?

texts:
I'm trying to calculate the checksum of IPv4 and UDP messages coming out of my Ethernet controller module. The checksum calculation for both IPv4 and UDP is defined as 1's complement addition, which means add most header fields and the entire message payload by 16-bit operands, add the carries back into the operands, and take the bitwise NOT of the result.
I can do this in a staged approach. I first calculate the checksum words in this manner as the message is received (outside of the block in question - that does just fine). I then pass this along with the message itself to the next block, which needs to calculate both the IPv4 and UDP checksums before the IPv4 block writes the IPv4 checksum field. It does this in stages, halving the number of operands. But I still need to calculate carries afterward, and all of this together means the final answer IPv4 checksum doesn't propagate through in time to be written in the checksum field. Here is a snippet of the first few stages of my adder tree (concat_string : std_logic_vector(15 downto 0) := "0000000000000000";):
-------------------- IPv4 CALCS --------------------
      -- Stage 1 sums
      isum1 <= unsigned('0' & vide)                        + unsigned('0' & eth_len_int(15 downto 0));
      isum2 <= unsigned('0' & ip_id)                       + unsigned('0' & offset);
      isum3 <= unsigned('0' & TTLProto);
      isum4 <= unsigned('0' & ip_src(31 downto 16))        + unsigned('0' & ip_src(15 downto 0));
      isum5 <= unsigned('0' & ip_dest(31 downto 16))       + unsigned('0' & ip_dest(15 downto 0));
      isum6 <= unsigned('0' & src_port)                    + unsigned('0' & dest_port);
      isum7 <= unsigned('0' & tcpudp_len_int(15 downto 0)) + unsigned('0' & tcpudp_chksum_int(15 downto 0));
      -- Stage 1 carries
      ic1   <= unsigned(concat_string & isum1(16)) + unsigned(concat_string & isum2(16));
      ic2   <= unsigned(concat_string & isum3(16)) + unsigned(concat_string & isum4(16));
      ic3   <= unsigned(concat_string & isum5(16)) + unsigned(concat_string & isum6(16));
      ic4   <= unsigned(concat_string & isum7(16));

      -- Stage 2 sums
      isum8  <= unsigned('0' & isum1(15 downto 0)) + unsigned('0' & isum2(15 downto 0));
      isum9  <= unsigned('0' & isum3(15 downto 0)) + unsigned('0' & isum4(15 downto 0));
      isum10 <= unsigned('0' & isum5(15 downto 0)) + unsigned('0' & isum6(15 downto 0));
      isum11 <= unsigned('0' & isum7(15 downto 0));
      -- Stage 2 carries
      ic5    <= unsigned('0' & ic1(15 downto 0)) + unsigned('0' & ic2(15 downto 0));
      ic6    <= unsigned('0' & ic3(15 downto 0)) + unsigned('0' & ic4(15 downto 0));
      ic7    <= unsigned(concat_string & isum8(16))  + unsigned(concat_string & isum9(16));
      ic8    <= unsigned(concat_string & isum10(16)) + unsigned(concat_string & isum11(16));

      -- Stage 3 sums
      isum12 <= unsigned('0' & isum8(15 downto 0))  + unsigned('0' & isum9(15 downto 0));
      isum13 <= unsigned('0' & isum10(15 downto 0)) + unsigned('0' & isum11(15 downto 0));
      -- Stage 3 carries
      ic9    <= unsigned('0' & ic5(15 downto 0)) + unsigned('0' & ic6(15 downto 0));
      ic10   <= unsigned('0' & ic7(15 downto 0)) + unsigned('0' & ic8(15 downto 0));
      ic11   <= unsigned(concat_string & isum12(16)) + unsigned(concat_string & isum13(16));

I know there should be a way to calculate [sum = unsigned(x) + unsigned(y) + carry of x+y] written cleanly in one clock cycle instead of two. What's the most legible way to do this?


texts: How can find the voltages at 2 nodes with 1 equations and 2 variables?

texts:
simulate this circuit – Schematic created using CircuitLab

At node 1, we have:$$0.001+i_1-i_4-i_5=0$$.
At node 2, we have: $$i_4+i_5+i_2=0$$.

$$i_1=\frac{0-V_1}{1000}=\frac{-V_x}{1000}$$(Vx is the voltage across R2)
$$i_2=\frac{0-V_2}{6000}$$
$$i_3=0.001A$$
$$i_4=i_1+i_3=-i_2-i_5$$
$$i_5=\frac{V_1-V_2}{1000}=\frac{V_x}{1000}$$

Use the equation at node 1, to find an expression for i4 and plug that into the equation at node 2: $$i_1+0.001+i_2=0$$
$$\frac{-V_x}{1000}+0.001-\frac{V_2}{6000}=0$$

But there are V2 and Vx to solve in one equation.


texts: Response of a stable second-order transfer function to a unit sine wave input

texts:
In the lecture slides from my university it says that:

"The response of a stable second-order transfer function to a unit sine wave input is:"

$$Y(s)=\frac{1}{s^2+2\zeta\omega_n+\omega_n^2}*\frac{\omega}{s^2+\omega^2}$$

Isn't this missing an \$ω_n^2\$ in the numerator? Since the standard form of a second order transfer function is:

$$H(s) = \frac{\omega_n^2}{s^2+2 \zeta \omega_n s + \omega_n^2}$$

and the laplace transform of the sine wave input is:

$$\frac{\omega}{s^2+\omega^2}$$

Is this a mistake in the lecture slides?


texts: arduino power problem when using boost converter

texts:
I am making a bot capable of solving a maze.

I will explain the setup first. There is a 18650 3.7V battery, using a XL6009 DC-DC boost switching regulator, like this one:

Picture Source

I boost the voltages up to 9.5V. Then I make 2 parallel lines. One goes to the Motor Driver voltage (motors work fine at 10-12V). The other end goes to the Vin of the Arduino.

When I attempt to test the motors, the Arduino sort of resets everytime although it works fine if I test some other peripherals and disconnect the motor driver and hence the motors.

Again the motors work fine, if I power the Arduino separately like from a 9V battery keeping the rest of the circuot as it is.

What am I doing wrong?

Will connecting a linear regulator like 7809 / 7805 in series before powering up the Arduino help ?


texts: Power supply architecture for energy metering IC (HLW8012)

texts:
HLW8012 datasheet (mostly Chinese)

Website with english info

I am developing a product which requires energy measurement of two different phases. I am planning to use HLW8012 energy metering IC which has this application circuit:

In this circuit, GND is referenced to 220 VAC on 1 milliohm shunt resistor.

Since GND is referenced to 220 VAC, the circuit uses NEUTRAL line on V2P for sensing voltage.

Q1) Can I reverse these two things? - I want to use GND referenced to NEUTRAL and use LIVE (220 VAC) line on V2P for sensing voltage. (please refer to the circuit below):

Q2) As mentioned earlier, I need to measure energy on two different phases (neutral line is common for them). I want to keep total circuit size small. Can I use same power circuit to power both circuits as shown below:

Details - Power supply circuit will be non isolated type with neutral connected to GND.

Note: R8 (1K) is my shunt resistor. Actual value will be 1-2 milliohms.

Note: R17 (1K) is my shunt resistor. Actual value will be 1-2 milliohms.


texts:
Can someone please clarify how a PLL works and how it can the result is used to deduce phase?

My understanding is that a PLL is used to demodulate in situations when the demodulator knows the carrier frequency but does not know the phase.

The expression of e(t) can be computed by

1)$$
     e(t) = u(t)S_i
$$
2)$$
     u(t) = v(t)S_i
$$

where

3)$$
     v(t) = \sin f(t)
$$

4)$$
     f(t) = \int_0^t ( \omega _ c + c e(\tau) ) dt = \omega _ c + \int_0^t c e(\tau) dt = \omega _ c t + \theta (t)
$$

5)$$
  u(t) = \cos ( ( \omega _c + \Delta \omega )t + \phi ) \sin ( (\omega _ c t + \theta (t) ))
$$

6)$$
   u(t) = \frac{1}{2} \left( \sin ( (2 \omega _ c + \Delta \omega )t + \phi + \theta (t)  ) + \sin ( \theta (t) - \phi - \Delta \omega t  )   \right)
$$

It's clear that passing u(t) through the LPF will give

7)$$
    e = \sin ( \theta (t) - \phi - \Delta \omega t  )
$$

8)$$
    \Rightarrow \theta (t) = c \int_0^t \sin ( \theta (\tau) - \phi - \Delta \omega \tau  ) d \tau
$$

Which seems like an impossible integral to compute.The question now becomes, how does this help us determine phase? we have transformed a function of phase.

I have seen plots of theta against t being plotted, such as the one below which was supposedly plotted with the parameters as

9)$$
   \omega _c = 2 \pi 1250 ,\hspace{2mm} \Delta \omega = 2 \pi 0.2 ,\hspace{2mm}  \phi = \frac{ \pi}{4}, \hspace{2mm}  c = 10.
$$

From the looks of it looks like

10)$$
   \theta (t) = \Delta \omega
$$

as t tends delta omega as t tends to one, which doesn't seem to make sense.Can someone shed some light on how we get the phase from a PLL, I'm really stuck on this.


texts: Running an alternator and SMPS in parallel

texts:
Can one connect a car alternator and a switched mode power supply in parallel on a network and run them at the same time without damage to either component?

My understanding given their implementation is as follows:

car alternator is a 3-phase stator rectified by diode. Excitation voltage controlled by a voltage regulator circuit which stops excitation if voltage on the alternator output is higher than a threshold.
looking into an SMPS, there are the smoothing transistors preceded by the rectifier diodes which rectify the transformer voltage. Voltage is controlled by PWM with the help of voltage sensing at output.

In consequence:

It should be ok to connect both in parallel as both have internal diodes which avoid short circuits.
If one sets the SMPS at a higher target voltage than the alternator one has a "priority" configuration in which the SMPS supplies (virtually all) the power to the network when it is switched on.
When it is switched off, the alternator takes over power supply seamlessly.
The smoothing capacitors in the SMPS will help to smooth the voltage in the network produced by the alternator (3-phase ripple) even if the SMPS is off.

Can anybody confirm this reasoning before I go and produce a cloud of smoke?


texts: current in resistor in series with voltage and current sources?

texts:
What would be the current in the 3 ohm resistor next to 45v source?

Im not sure if it should be 45/3 or 5 amps!


texts: Constant Current Load fails to recover after setting load to zero

texts:
I'm trying to design a Constant Current load for testing battery cells using the TLC070 Op Amp (what I happen to have on hand) and a low pass filtered (150Ohm + 470uF cap) PWM input from an Ardiuno. The OpAmp is driven by a 12v rail and the Arduino by 5v supply, all sharing a common ground.

The circuit is based off of this one:

The issue occurs if I set the input voltage to 0V, the Op amp will not drive the MOSFET (IRFZ44n) again. If the PWM is set to anything but 0, and the power to the OpAmp is turned on, the circuit works as advertised.

Is there a way to solve the issue turning on the CC Load from a 0 input PWM signal to a higher PWM signal?

Thanks!


texts: Paired Polarized Electrolytic Capacitor to Form Non-Polarized

texts:
A quickie...

I needed a 1uf non polarised cap for a circuit which I didn't have so I found info that said I could join the + of two polarised caps and connect the two - terminals into the circuit to create a non polarised electrolytic cap.

I understand I should not exceed the reverse breakdown voltage in either direction and that the capacitance will be halved but are there any other issues (I also understand electrolytics are leaky)

Bash me by all means


texts:
That is the motor.

Looks like the old version of a new Baldor M3558 2HP 3phase motor.

I plan to run a 230v 3phase line to the motor, but I need a starter.

This starter on Grainger looks promising:
https://www.grainger.com/product/SQUARE-D-Magnetic-Motor-Starter-19YA92

But my motor specs are 7A and 2HP

...and that starter, which is the closest I can find, is 18A and 3HP.

Is it OK to supply that extra 1HP? Is the 18A in the starter to cover for starting voltage?


texts: Transfer Function of Circuit with Transformer

texts:
I am trying to confirm the results for the transfer function of the circuit shown below. However, I don't seem to get any near the given solution. My main question is if someone knows how is the transformer considered (accounted for) in this analysis? Also, I would appreciate if someone can direct to the solution or setting up the main equations for the mesh analysis.

The author gives some directions on how to approach the analysis: "When analyzing the power link in Figure 3, the source of the uplink can be considered as a short circuit. By leveraging the mesh-current technique [22], the voltage and current transfer functions of the power link are derived as shown in Equations (1) and (2), where M=k(LoLi)^0.5 is the mutual inductance between the coils and s is the Laplacian. Equations (1) and (2) will be used to calculate the PTE in Section 4.1.3. The relation between Vo(s) and Vload(s) is denoted in Equation (3). Equation (3) will be used to calculate the power carrier amplitude on the out-body coil in Section 4.1.1."
Thanks for the help!
Note: This is an open access paper titled "An NFC on Two-Coil WPT Link for Implantable Biomedical Sensors under Ultra-Weak Coupling" and all the credit goes to the authors: Cheng Gong, et. al.


texts: How battery-charger system in mobile phones and laptops works?

texts:
It was 5 am in the morning stuck at McD and waiting for the train with my friends. All out of nowhere I asked them this question that I have been thinking about for some time.

How this battery-charger system in mobile phones and laptops work?

What I don't really understand is the ratings thing.

Lets assume that, the charger is 5V, 2 Amp
And the phone battery is 1 Amp and (5V)

I know that means the phone is going to be able to take 1 Amp for charging from this 2 Amp rated charger. But

First is the phone battery Voltage 5V?
Second how will this battery ONLY takes this 1 Amp, as from ohm's law the current is
I=(V-charger - V-battery ) /R
Here is an assumption, the phone battery is changing( from some min voltage value when the phone is 0% charged to  max voltage value when its fully charged). Consequently the voltage value
(V-charger - V-battery ) will chane as well
So how will this drawn current be constant while the voltage
is changing?
Is there any current limiting diode? Any current mirror?

Is this the mechanism of this system works?


texts: What are the caveats of placing PSoC 4 variables in flash?

texts:
PSoC4 chips have only between 2 and 4KB of RAM. That's not much, especially if I want to do some data processing. Between 16 and 32KB of Flash seems much more promising, even if I need to share it with the code. Thanks to the "Flash Accelerator" it seems one can use Flash the same way as one would use SRAM, only at cost of a minor performance drop. There's a document that describes how to do it, and it seems quite trivial:

in Project > Build Settings > Linker > Command Line > Custom Flags add:

     -Wl,--section-start=.MY_SECTION=0x00001000

then declare your variable as:

     uint8 variable1 __attribute__ ((section(“.MY_SECTION”)));

(that is using GCC, as PSoC Creator does "out of the box").

Now if I understand correctly, the first thing to consider is the standard 100k write cycles that standard PSoC4 chips have. Performing 100k writes to a variable can take a very short time; does the "accelerator" protect the cell or do I risk damage to the chip with a simple for(uint32 flash_var __attribute__ ((section(“.FLASH”)))=0 ;flash_var<100000;flash_var++){...}?

Next - can I expect the variable to persist its value across power loss, or do I need some extra wizardry to obtain this functionality?

Does that play nice with bootloader in bootloadable applications, or do I risk overwriting the bootloader or something like that?

What other considerations concerning that kind of variables should I have in mind, that I haven't thought of - and which I'd likely learn only "the hard way" if I don't ask?


texts: Can I use Mic to input Frequency Meter circuit?

texts:
Í'm new to application level of electronics that I'm studying.I have a project to do in college and I was thinking to do a Frequency Meter circuit that can measure the frequency of given input signal and display it on an LCD display.

I using this circuit as reference:

I wondering if I can use input from a mic to measure the frequency of sound ( human voice or anything )

Hep appreciated very much!


texts: Does a Microcontroller act as a Capacitive load or resistive?

texts:
I'm designing a unity gain buffer (IC MCP6002) and in the datasheet, it says that a  small series resistor is required at the output, if the load is capacitive and is >100pF.
The input of the buffer is a varying ADC value from one microcontroller and the output of the buffer is given to the ADC input pin of a second microcontroller.

Is the microcontroller at the output considered a capacitive load in any way?


texts: Faraday cage with a RF WIFI router inside - does the electricity "evaporate"?

texts:
I have a Faraday cage and inside there is a WIFI router whose RF I am trying to contain. The cage is made of aluminium mesh with hole sizes of 3 mm or so.

What happens to the RF electricity coming from the RF WIFI router and hitting the Faraday cage (from inside) if I don't ground the cage?

Would the electricity "build up" inside/on the cage and in what form since it will cease to be RF?

I have had the RF WIFI router emitting for few hours however I cannot detect any voltage increase on the cage's surface.

I measured for DC and AC using a multimeter and the values remain constantly the same - about 4 volts AC.


texts: What is the power of a three phase circuit?

texts: P = sqrt(3)*U * I * cos(f) is the real power for a symmetric load (U and I are RMS values of voltage and current of a single load), but what about generators?Do they have to have equal electromotive forces too?


texts:
So I just got my TI eZ430-Chronos Dev kit (a runners watch & eZ430 micro dev combined), and I am chomping at the bit to start playing around with my new toy. I have just a few issues the recommended tools from TI are Windows based, and I am lacking a valid windows OS right now.  Also I brought the watch back to work, but left the programmer and AP at home.  So I am left reading articles and links to wiki's, but unable to try anything out for myself.

Stuff I have read so far:
http://www.linuxjournal.com/article/8682
http://wiki.msp430.com/index.php/EZ430-Chronos
http://sourceforge.net/projects/mspgcc4
http://blog.makezine.com/archive/2010/01/ti_ez430_-_chronos_development_kit.html

I also searched the mspgcc sf mailing-list, it had no mention of the chronos.

Has anyone been able to get mspgcc or mspgcc4 to work with the Chronos. I have searched for
information about this on the various sites, but found no answers.  It should be very straight forward, but I will give it a shot later and report back if I don't hear back.


texts: Variation of the amplifier input impedance by the temperature

texts: I have a question, How can I calculate the input impedence in amplifier when the union base-emitter temperature is different (25C 100C, 50C ...)?


texts: Designing simple class a amplifier using mosfet

texts:
I'm trying to build a simple class a amplifier using a mosfet. I have read few articles about how to do it, but I'm just confused now. I'm not sure how to select resistor values. The articles I've read show how to calculate this values, but the requirement is conduction parameter "k" which is not in documentation for transistor I have(IRFZ44N). I tried calculating this value from equation k = Id/(Vgs-Vth)^2 after measuring current and voltages for different gate voltage, but the "k" I get isn't constant.

I also tried selecting resistor values without calculations and with that I have the most success, however the output signal is not amplified, it is diminished.

I chose Rd so that Vd is Vcc/2. R1 and R2 set gate voltage to 4.8V, because gate threshold voltage is 3V and sawtooth amplitude is 500mV(I can set Vg lower, but it doesn't change much).
I'm not sure about Rs. The 8.2 Ohm resistor is a "speaker".

Why is the signal not amplified? I realise that the answer might be complex, so I would be also grateful for some good study material books/tutorials etc..


texts: Why do I get this waveform at the output after power down of Buck Converter

texts:
I am having a buck converter which steps down 8-16V input to 5V output. Load current = 0.6A
But upon removing the input power, I get the attached waveform.

My schematic circuit is similar to the one in this datasheet's application diagram on page 29.

Please let me know why I get this waveform upon removing the input voltage instantly?

Thanks


texts:
I am a bit confused about the difference between current and power. I am hoping someone can explain the difference to me maybe using an analogy or something.

I do understand that current at a point is a measure for how/much charge (in coulomb) is passing through the point (per second). I think I understand Ohm's law which says that over some component with fixed resistance R and voltage drop V there will be a current of \$V \over R\$.

I understand that power is much energy in joules is "deposited" in the component per second.

Some examples of where my confusion comes from: Usually when one buys appliances they have a wattage rating. So, my microwave oven uses (up to) 800 W. So it seems that wattage is the important thing to understand in many cases.

A power supply is (from what I understand) usually given with a (max) voltage and a (max) current. Why is the wattage not given here?

If I have an LED that can handle maximum 3V and I also have a 9V battery, I would need a resistor. But to find the size of the needed resistor I need to know how much current the LED uses. I have been told that one should find this in the datasheet of the LED, but that LEDs rarely come with a datasheet when you buy them. I have been told that it is common to assume that the LED uses about 20 mA. So I can understand how I can calculate the needed resistor. Where does the wattage come into to this situation? Why isn't the wattage listed?. Also, if one has a complex circuit that can handle only 5V, but one only has a 9v power source, then how would one know the current?

Maybe my confusion is that it seems that a certain current should always give a certain wattage.


texts:
I have a Syemour Duncan guitar effects pedal that I bought several years back. I seem to have lost the power adapter for it and they don't make them anymore. I looked at the power input on the pedal and it says 16V~ / 560mA. The manual says

  Do not try to substitute a DC power supply or another AC supply with a
  different voltage or current rating.

They give a website where you can buy a replacement adapter, but the only applicable replacement I could find is no longer carried.

However, I did find this adapter on amazon. The voltage matches but the current is 1000 mA. It's my (fairly uninformed) understanding that it's okay for the adapter's current to be higher than the device's. At least that supposedly true for DC current. Not sure about AC. Would the amazon adapter be safe to use?

I also notice that the amazon adapter lists the plug as being 2.1mm. I'm not sure if that's compatible with my pedal. Is there anyway to know?


texts:
Given this initial circuit:

simulate this circuit – Schematic created using CircuitLab

After some time(\$ \Delta t\$) there are multiple induced EMF's within the third branch leading to the following:

simulate this circuit

At the third branch, will the net-voltage Always be: Applied + EMF2 - EMF1?


texts: with a bq24190 charging IC how can I feed the usb bus when in host mode (OTG)

texts:
I'm fairly new to this and I am trying to build a board around a stm32f750z8 and I'm on the USB OTG/charging part.
The board will have only one USB port in OTG mode, and the mcu will be powered by the battery/usb, no other external power, the external device (in host mode) can be an HID peripheral, flash disk, etc. and will be powered by the board. In device mode, the board will be powered by USB (and charging the battery).
I've found the bq24190 IC that can handle USB OTG and battery charging but I have issues understanding how to manage the "usb host" condition (delivering power to the usb device connected, from the battery).
I have wired the USB VBUS to the stm32 USB_OTG_FS_VBUS pin (PA9) which seems to allow detection of device vs host, but I can't figure how to powers the USB VBUS if I want to like use a flash drive in OTG.
I have seen others stm32 mcus with an usb otg enable pin, used to trigger a power switch, but here I'm lost at what I should do.
The bq IC does have an input pin OTG that can trigger a boost mode but I can't figure what that means exactly here.
So my big question is how can I powers the USB BUS while in host mode and not in device mode ?
Here is the actual schematic of the power part:


texts: How feasible is it to edge plate a PCB or at least a portion of one? I've seen it done but as I understand the outer edge is only cut after plating at most fab houses. Is this something that's commonly possible? I'm currently working on a board that would benefit from this as it slides into a metallic case and needs to be connected to it.


texts:
I'm having difficulties anlysing the USB Type-C Spec R2, section 4.6.2.1 "USB Type-C Current" paragraph. It is said that "When a Source is advertising USB Type-C Default current, the Sink behavior is defined as follows: [...] It attaches as a USB Type-C Power Sinking Device (PSD), after which the Sink may draw up to 500 mA. ". I'm not sure if the USB Type-C default current advertised is referring to the USB 2.0/3.x:0.5/0.9A (which I think is the case given the previous paragraph) or the 1.5/3A usb type-c current.
The former interpretation would be a violation of the USB 2.0/3.x, since you can't draw more than 100mA without enumeration. The latter would mean that every website saying you only need to monitor the CC lines to draw up to 0.1/1.5/3A depending on the state of CC is wrong, and I would also not understand the whole point of the CC current advertisement.
Given the use of "default" in the previous and next paragraphs I believe it's the former interpretation. Am I wrong to believe there's a violation?


texts: Amplifier with true ground output swing and A/D conversion

texts:
I want to amplify a 0-20mV signal from a sensor to 0-2.048V in order to feed it to an ADC (with a reference voltage of 2.048V).
After I will input the digital signal to a microcontroller.
I need to be able to detect a change in the 0-20mV signal with an accuracy of 5µV. Thus after amplification to 0-2.048V (using a gain of 102) an accuracy of 0.5mV is needed. My sensor signal changes very slowly and I only need to take one sample/measurement per second.

I have chosen this instrumentation amplifier for amplification (differentially) AD8237: Datasheet

Now in order to get a true ground output swing (as the signal is in the 0-20mV range initially) I want to use the LM7705: Datasheet

By powering the positive supply Pin of the AD8237 with 3.3V and the GND Pin with this little negative ground from the LM7705 I should be able to get an output swing to zero volts (thus, use the whole range of my ADC). The LM7705 Negative Bias Generator seems to be made exactly for this purpose. I tried to check this idea with the Diamond Plot tool by Analog Devices and everything seems to be in the expected and valid range:
Click to view my configuration

Also regarding the accuracy, the biggest issue I see is the input offset of 75µV of the in-amp, but I should be able to correct the value later in software (calibration).
Do you see problems regarding the small negative ground supply for this instrumentation aplifier? I couldnt find anything against it in the datasheet. (To the ref pin I would connect the normal ground of 0V). Is that ok?

Further, I chose this 18Bit ADC (MCP3422):
Datasheet

Would also power it with 3.3V and connect the in-amp output directly to this ADC (single ended). It has an on-board reference voltage of 2.048V.

Can I connect the in-amp output directly to this ADC?
Do you see big problems with this approach or ADC and its accuracy (so I can meet my specified minimum requirements)?

I appreciate every hint/feedback/help I get from you, thank you!


texts: How to control a unipolar stepper motor (2A/phase) with MOSFETS

texts:
I want to control my stepper motor (103H7123-0440) with MOSFETS (IRFB31N20DPBF), however the stepper doesn't turn. I can't understand why it has problem and I would appriciate any help. I have attached the circuit diagram. The MOSFETS are controlled by an NI module (NI9263) which is connected to a cRIO 9045.

To visualize I have also replaced the stepper motor with some LEDs (each LED represents one coil-diode pair). And this works properly. This confuses me more why the stepper motor doesn't turn.


texts: Is there any standard (or even a de-facto standard) for TRRS to USB?

texts:
I've had a few MP3 players that used a single 3.5mm TRRS jack for both connection to earphones and for connection to a USB port (for transferring music files and re-charging the player.) To that end, these players always came with a short adapter like this image.

I've traced the wiring in these adapter, and have found them to be straight through (no apparent internal components I can detect). So I would like to use a similar scheme to provide USB access to some of my MCU based projects that are mounted within small enclosures. A TRRS jack has the advantage of mounting in an easily (and neatly!) cut round hole, that takes up very little space. They also tend to be much cheaper than special purpose panel mount USB ports.

But sadly, I don't seem to be finding ANY consistency in the wiring of similar adapters. If there were, I can see where it would be easy to find both female and male versions, but the few I've found have lead to disappointment. Recently, for example, I thought I had a great find on ali-express, a short cable with a male USB-mini on one side, and a TRRS female on the other. Eureka! I thought! Now I'll have an easy connection to my MCU's female mini, and won't have to resort to hand soldering what I put inside the enclosure. But not only did the wiring NOT correspond to the adapter in my picture here, also didn't even have all 4 connections!

So is there any standard here? Have any been proposed? Since lots of those  MP3 players used 3.5mm TRRS jacks for their USB access, I would have thought  manufacturers would draft some kind of de-facto standard. But GOOGLE is full of diagrams of such adapters, and i don't think I've found any 2 the same. :-(

EDIT: someone kindly pointed me to a similar question, which did at least let me know I wasn't alone in my quest for this, and did point out at least one "pinout' for for a TRRS USB (which was  NOT ideal IMO). But I'll let the question stand only because the one referenced was over 5 years old, and the answers were fairly limited. Maybe some things have changed since then, so any new experiences of others will be valuable to me.

EDIT2: I forgot to mention that what was referred to as the "most commonly used pinout in the referenced similar question was indeed the same pinout as the one in my picture, namely...

Tip --> D-
Ring1 --> D+
Ring2 --> GND
Shield --> VUSB

My player wasn't among those mentioned, so maybe some un-officially documented standard has emerged. The pinout is certainly not ideal for a USB situation, providing way too many opportunities for shorts with the 5V being the shield. It probably was designed to make interface to ordinary earphones easier, because on the female side there would be no 5V on the shield (or "sleeve" ) connection. It still would likely be a useful cofiguration in situations where an MCU already has power from another source, so that would become an NC on the female side.

So... but...if that many companies use this pinout, maybe there is my a hope that som other compatible adapters exist!


texts: Why does VGA have so many ground pins (compared to DVI-I for example)?

texts:
If you look at the pinout for VGA, there are several ground pins:

I was curious as to why, and I found this answer. To sum it up, the extra ground pins are so that each pin has its own ground in order to prevent interference in the analog signal.

But here's a DVI-I connector that supports analog signals:

The analog pins are on the right side. The big cross is ground, and the four smaller pins surrounding it are for the red, green, blue, and horizontal sync. What is interesting here is that the ground is shared by all three color channels, unlike VGA where each has its own.

Why are the additional ground pins necessary to prevent signal interference when using VGA but not DVI-I? They're the same pins that send the same data, just with a different physical connector, so it doesn't really make much sense as to why the number of ground connectors are different.


texts:
I am on my first projects in electronics to refresh my old rusted knowledge and to updated also.

I have a not so stable input about 12v to 15v maximum and i want to convert it to 9v and use it to recharge 9v batteries (9v Ni-Cd 160 mAh and 9v Ni-Mh 300 mAh)

I dont want much heat or too many components on it cause of little space for the circuit so i would like to try as my first projects to make it with zener diode and a resistance but since i am like noob in this area and search around didnt came up so handy and understandable
i would like to know first of all if it can be done in this way and if is possible to stabilize an input of 12v - 15v to 9v for my batteries and what zener type do i look for and what combination of resistance with zener ?

Thanks in advance


texts: What would happen with a 25W bulb (g4) in a 20W socket?

texts:
I have a 20W (12V) desk lamp and a 25W (500 lm) bulb, type = G4/halogen.
I know putting a 75W bulb in a 60W socket can damage it or cause it to break.
In my situation there is only 5W difference.

Would the extra 5W damage the lamp?
Is it very dangerous?
What could happen if I put the 25W bulb in?

I can't find a suitable answer on google so I thought I better be safe and ask stack exchange.
Edit:
Here is a picture of the lamp if it helps:


texts: Rechargable Li-Po battery to power Arduino through ICSP header?

texts:
I have a Arduino Uno.
http://arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf

I want to power Arduino using rechargable Lithium polymer battery,
through ICSP's 5V and GND pins.
ICSP might not be the best place, but I want to know if ICSP is possible for this, because every Arduino has it.

So when the Arduino's USB is connected to PC and Arduino is able to get power from USB bus, I want to charge the battery through the board on top of ICSP pins.
When USB is disconnected, and the battery is full, my board provides 5V to Arduino.

I understand that my board needs a current control IC (ex: max1555) to safely charge Li-Po battery, and a way to convert Li-Po's voltage to 5V.

Is there something else that I have to worry about?
Does Arduinos accept 5V from ICSP and work properly?


texts: Why does an uncharged capacitor short out a resistor in a basic DC circuit?

texts:
I’ve really only dealt with two laws thus far concerning circuits and capacitors:
$$V=IR$$
$$Q=CV$$

The first obviously being Ohm’s law and the second the equation for a capacitor’s charge. I’ve seen many circuits with uncharged capacitors put in parallel with a resistor, and the solution always says the uncharged capacitor shorts out the resistor—all the current goes through the capacitor, not the resistor. This applies for the instant when the switch is closed, at least. But I don’t understand why that is. When the switch closes, I assume that the voltage across the resistor is 0, seeing as its charge is 0. But a capacitor doesn’t have a ‘resistance,’ does it? What would be its analog, and what equation would relate that quantity to current and voltage? Does Ohm’s law even apply here? Why, mathematically, is I infinitely large for an uncharged capacitor (i.e. short circuit)?


texts:
My Sharp Carousel microwave oven (model R-303CW) display has been flickering off & on recently (mostly it appears to be off).  When it appears to be off, the display characters are actually very dimly lit.  If I shine a light onto the display at the right angle, the correct display characters (i.e. clock, timer, etc) appear to be almost as bright as when the display is working properly.  The display output should appear the color & brightness of the last image below (which is not of my actual unit).  I've included a few (hopefully useful) pics below.

Is the cause of the problem some kind of LED back-lighting malfunction??  If yes, how is that implemented to shine light onto the reflector that is behind the display lens?  The display looks like a piece of glass with the LCD characters produced inside the glass.  There is a florescent green paper strip behind the display lens which imparts the yellow-green color that the characters usually appears as when the display is working properly.

I did not see any obvious problem when viewing the circuit card.  If anyone knows what the cause of this problem is, please let me know.  I thought the problem might be the ribbon cable (i.e. the upper ribbon cable in img 2) that connects the LCD display & to the display control circuit card; however, after pressing firmly along the ribbon cable on both ends while it was powered, there was no noticeable difference in the display output.  Thanks in advance for your consideration & thoughts!

A schematic can be viewed here.


texts: std_logic_vector to integer give always 0

texts:
I can't assign std_logic_vector to integer. What do I wrong?

signal data_out: std_logic_vector(20 downto 0);
signal d_value :  integer;

and in process

test: process(data_out)
        variable d_value_int : integer;
        begin
            d_value_int := to_integer(unsigned(data_out));
            d_value <= d_value_int;
    end process test;

I tried to do it like this, but it doesn't works too:

test: process(data_out)
        variable d_value_int : integer;
        begin
            d_value <= to_integer(unsigned(data_out));
    end process test;

Always my d_value isn't changed. It's 0 in simulator
I used snipet from xilinx which send here Blair Fonville and it doesn't works with my example. I have some differences, coz my a here is signal and b is signal and my code is in process. That's differences


texts: Designing a filter to achieve a specific frequency response

texts:
I am attempting to design a circuit which filters and amplifies an analog signal. The goal is to achieve the frequency response in the figure below.

I planned to use a second order active low pass filter with a gain of 24(A1) and a second order active high pass filter with a gain of 2(A2). However, my professor has recently given me feedback regarding my proposed filter design which simply stated "This will not work".

I understand this graph appeared in another question but I could not understand what was being asked so I will simply list my questions.

1) Why would my proposed filter design not achieve the required frequency response?

2) What other circuits could produce this frequency response?

Note: I have looked into summing amplifiers but I am not sure how you could separate the HPF and LPF to match the gains at A1 and A2 without the signal bypassing the filter that blocks it since the summing amplifiers input branches would be in parallel.

The only restriction is we can't use digital electronics.


texts: Fourier Series of Convolution of Periodic and and Aperiodic Signals?

texts:
The impulse response of an LTI system is aperiodic and I pass in a periodic signal. Now I need to find the Fourier series representation of the output.

Since Convolution in time domain is multiplication in frequency domain, I think that converting both signals in their respective frequency domain and multiplying them would work.

Therefore, finding the Fourier series of first and transform for second. Is it a correct way?

My question being is it legal to multiply fourier series and transform the way I'm doing?


texts: Design a sequence detector to detect 1001 or 11

texts:
I want to draw a state diagram about the sequence detector circuit. The circuit will generate a logic “1” output is a sequence of 11 or 1001 is received. I have my answer, but I don't know my answer whether correct. Please help me check.

New result here:


texts: High Side Switch Implementation (Active-High)

texts:
I'm pretty confident in this circuit theoretically, but I wanted to run it past the EESE community in case there is some flaw in the design, maybe someone could point it out. If it's great, then the question makes a good reference for others seeking a similar solution.

So my design constraints are I would like to be able to switch up to about 350mA at 5V, and I would like the control signal to this switch to be 5V and active-high. That is to say, when 5V is applied to the control, the switch should be closed and allow current to pass, and when 0V is applied to the control, the switch should be open, and no current should flow into through. Default state should be off if control input is floating.

The circuit I have conceived for this purpose is pretty basic.

simulate this circuit – Schematic created using CircuitLab

... and I've identified a dual-FET package that should more than cover my requirements DMG6602SVT.

Any problems with this concept?


texts: How to research Hardware Theory in Vision Systems

texts:
I am trying to read up on the theory (for Hardware) of how hardware works in a Vision/Camera System from the Camera Sensor all the way to the pixels on the screen.

I dont know what to start googling to understand how the time domain relates to the spatial domain and the hardware in between (like in cell phones). What should I be searching for?

PS: Sorry in advance for the vague question, but looking for a direction.


texts: measuring the I-V Curve for the n-channel mosfet bs170

texts:
I've done with the Pi and the Waveshare A/D D/A High Precision a simple curve tracer. So far, it works perfectly for a resistor and a diode. However, I'm trying right know with the n-channel MOSFET (BS170), and the results are not that I expected and I don't know exactly why. I would appreciate if someone could explain to me why I got these results. For this, it was applied first a fixed voltage to the DAC0, while it was incrementing the DAC1 from 0 to 5 V, by steps of 0,5V. When the process finished, it was incremented the DAC0 voltage by 1 V, and it was repeated the process with the DAC1 until the tension generated in both DACs is equal to 5.0 V. The characterization circuit is presented below as well as the obtained curves.

Id vs Vds

Id vs Vgs

Id is calculated as Id=(vcc-vds)/R


texts: Protect phototransistor from emitter-collector breakdown

texts:
I'm using the ADC on the reset pin on an ATTiny85 to detect an IR level. The reset pin is disabled in the fuses but I would like the ability to "recover" the fuses and reprogram the device.

The emitter-collector breakdown voltage of the phototransistor is minimum 5V. During programming, 12V will be applied to the emitter. The collector will either be at 0V or 5V depending on the state of another pin during programming. Best case, there will be 7V from emitter to collector. Worst case, there will be 12V from emitter to collector. Both of these will result in the destruction of the transistor. The schematic below shows this in a much clearer way.

How can I protect the phototransistor against breakdown?

simulate this circuit – Schematic created using CircuitLab


texts: this is a DC Continental Electrical C0. Model D16  generator that came with the Fairbanks Morse hit and miss motor I restored. It was used to generate electricity for a farm house. I can not find any info on Internet for this generator. I would like to clean and restore it for use. My question is how was this supposed to power a farmhouse? I would like to run something for show. The spec label " Type D16, volts 9.12, kw .120, rpm 1350, winding CPD, amps 12,cont duty.


texts:
First I want to ask, why are S and R inverted when comparing an S-R latch with NAND and NOR gate. It just seems odd to me that they're being inverted.

Secondly, why is a multi-transition behaviour a bad thing to happen? Does it just overflows the circuit or something? If S and R both don't get 0 - 0 or 1 -1 at the same time ( depending if NOR or NAND), there shouldn't be a problem with the circuit ( unless I'm seeing this wrong)

With the same train of though, another problem arises when you allow flip flop to be cascaded if the S and R inputs ( again, that is how I understood it, I might be completely wrong) are not stable before and after the transition state of the clock.  Why would that be a problem? I still can't see the issue here.

Another question I have is, when we do a complete truth table, we use the input Q(t). Why would we use the current state in the truth table? isn't redundant to put the present and next?

Lastly, is an excitation table just a simplification of the complete truth table?


texts: How to excite a fluorescent lamp without connecting it?

texts:
I'm a newbie in electrical engineering, so this might be a silly question. But are there any standard ways to create an electric field over a volume of air, strong enough to excite a compact fluorescent lamp?

I've seen these videos where people use plasma globes to do this. The electrical field outside of the globe is strong enough to do this, so there must be some way of achieving this.

To give an idea of the shape of field I need, imagine a conveyor belt with fluorescent lamps on it, which pass by. I would need to aim an electric field as such that the fluorescent lamps light up as they pass by.

Any help would be appreciated!


texts:
In several area's of Intel's atom e38xx data sheet, and programmers volume 3 datasheets I see references to the word EPROM. For example in programmer's architecture manual volume 3 I find this, The EPROM containing the
software-initialization code must be located at this address.

I thought the first code of execution lies in the flash device? Can I assume they mean flash? In the intel atom data sheet it shows memory map and in the DOS section there are two eprom sections. I know the device supports to SPI flash so I assume this is MMIO to the SPI flash even though it calls it EPROM.


texts: Source Transformations resistor on bottom?

texts:
I know that source transformations work as shown in the top part of the attached image but what happens when the resistor is placed in a different location?

Does this give the same result? If so, how do I know which where to place the resistor if I performed the transformation the other way around i.e. from Norton eqv to Thevenin eqv?

Sorry for the poor quality of the image.


texts: Help need controlling linear actuators on my car project

texts:
Looking for some electronics guru who can help with my car project.  Personally, my skill level/experience is below novice.

I have an ISIS system controlling the car electronics, including two of their optional components that allow me to control items via an ISIS supplied RF transmitter as well as an android smartphone.

Linear actuators open/close the doors and are controller by an Autoloc motor controller.  You can program the run time for an actuator and when the motor controller sees a ground signal, it runs the actuator for the programmed time and then stops.  Next time the motor controller sees ground, it reverses the polarity and runs the actuator in the reverse direction for the same time.  If at any time during the up/down travel, it sees a ground signal, it stops the actuator.  When it sees ground again, it reverses the polarity and the actuator runs the same distance in the opposite direction.

The problem:

The motor controllers allow for a certain amount of adjustability for "sensitivity".  Even on the controllers highest setting, it is sometimes not enough to operate the doors.  There is no binding, the actuators have well over the weight rating needed and in fact work 100% of the time if I run power directly to the actuator motor.  When the doors are acting up/stalling on the open cycle, very slight one finger pressure assisting allows it to run the full travel without stopping.

I have searched for other motor controllers that might allow more adjustability of the force, but have not found anything with the features I need.  So I am left with trying to improve the ones I have or finding another product to try out.

Here is a link to see the actuators working: https://www.youtube.com/watch?v=eHSa6tjS6PI

Also, I attached a picture of the different parts/how they work together.

Any suggestions are most appreciated!


texts:
I'm trying to develop a flasher circuit for an aircraft warning light like the one shown at https://flightlight.com/products/obstruction-lights-controls-faa-l-810/. The light will be powered with normal 120VAC providing 15 amps. I'd like to use transistors (BJTs, MOSFETS, thyristors, DIACs, TRIACs, etc.) to cause the light to flash (turn on and off at a given frequency).

Along those lines, I found several examples of transistor-based flasher circuits online, such as this one: https://www.electroschematics.com/4488/diac-controlled-led-flasher/ However, those circuits seem to all be intended for use in powering LEDs, which, I assume, have a lower current draw than the light I'm intending to use. Along those lines, I have a couple of questions:

1/ Will the circuit I linked to above work with the light I'm powering? If so, what modifications do I have to make to accommodate the higher current levels in the light I'm using?

2/ If this circuit does work, how do I modify the frequency of the flashing? I know it's possible to control that frequency by changing the values of the resistors and capacitor, but I don't remember the formula to do so.

3/ In the diagram for the circuit I found, it looks like the capacitor voltage has been set to 100V, presumably due to the value of the resistors. How do I calculate the voltage for that capacitor for a different resistor value?

Thanks for your help!


texts: How do I get the voltage of Ro to calculate the maximum power transfer?

texts:
simulate this circuit – Schematic created using CircuitLab
There is this circuit where I am tasked to get the maximum power transfer of Ro. Based on my understanding, I have to get its resistance and the voltage across it.
I calculated its resistance to be 1.674,(((2||3)+1 || 7)), ohms by using the concept of Thevenin resistance. My problem is that I don't know how to get the voltage across Ro to get its maximum power transfer.
I think using nodal analysis would help but I am confused as to what nodes I should be using to find Ro since essential nodes does not go to Ro.


texts:
I have a battery pack comprised of 2 6S 8000mAh LiPo batteries (link)
with each one connected to an individual BMS module (link).
I'm trying to charge the pack using a 25.5V dc power source as specified by the BMS manufacturer, using a 500W power supply I had which is fairly similar to this one. The BMS are connected parallel to each other.

Technically, the system works. However, the charge rate is very, very slow - to the tune of plugging it in at 22.2V, and 12 hours later it is only at 22.8V. What I am wondering is if there is something I am doing wrong, or perhaps something I need to add to my system to make it charge properly.

A few things that may be relevant:

I have added a few 220uf caps parallel to the output voltage of the power supply to reduce ripple
The power supply's output voltage sags down to the voltage of the pack while charging it.
While testing, I added a small-value resistor in series with the BMS in order to measure the current across it (my meter only goes up to 10A) - the pack was drawing about 16A, however this also caused the voltage supplied to the BMS to no longer sag (is this a good thing? Should I be charging with such a resistor installed?)

Any assistance getting this pack charging at more reasonable rates is much appreciated.


texts: High voltage input and low voltage capacitor in series safety

texts:
I’m working with a car battery that has a voltage drop when cranking the engine. As a result of this, the stereo restarts even though it was running already.

To resolve the issue of stereo rebooting due to low voltage current, I bought some capacitors that will sit in between the stereo and the battery to provide power to stereo until the battery’s voltage comes back up. I’ve decided to get high Farad (10-20F) capacitors, but I can only get any practical sized capacitors with high F that only have low voltage ratings (2.7v). So, I am in the process of connecting these in series to get the voltage to at least 12v. I am aware of the loss of potential F as a result of this, so my question relates predominantly to safety and failure -

Let’s say I connect six 2.7v capacitors in series resulting in 16.2v. Am I correct in assuming that the 12v coming in from the battery is safe enough for the capacitors to get charged without fail? Of course the negative end of the series will be grounded.
Is it safe for the capacitors to be connected to a power source (battery) 24/7?
If the stereo is not in use, would the capacitors use up battery’s power?

Thanks in advance for help!


texts: Can I Hook a Raspberry Pi Zero to a Laptop Display Via HDMI to TTL and TTL to LVDS?

texts:
Dilemma:
I have a project in which I am trying to use a Raspberry Pi Zero to display static content through a laptop screen. I am trying to make my unit as thin as possible and use as little power as possible. Previous searches have found solutions that would work, but are less than ideal for what I am trying to do. I would also like to mention that I am no electrical engineer and I struggle at reading datasheets and making sure I won't blow anything up, which is why I need your help.
An example of a previous solution: Some solutions mention using an LCD controller from eBay that had input and output in the form of HDMI, VGA, DVI and LVDS. However, these boards require something like 9V minimum, where I am trying to limit my build to a small 5V DC power supply. They are also massive in size and more importantly, height, which is also something I am trying to avoid.
Goal:
My goal is to be able to power the Pi from a 5V 2.4A DC wall adapter, and power the screen through the micro USB port (micro USB > USB A Hub > micro USB cable) so that only one small external power cable is required. Eventually I would like to see if battery power is an option, but as far as this question goes, I am concerned only about the 5V power supply.
My idea is to use an HDMI cable out from the Pi that goes to a 40-pin TTL breakout board that is typically used to power small TTL TFT displays and takes a micro USB in for providing power. From that board, I would take the TTL and run it through an LVDS converter board to try and output something that can communicate to the screen that I have available from an old laptop.
The screen datasheet can be found at: http://www.datasheetspdf.com/datasheet/B156XW02-V0.html
I ran out of links, sorry I'm new...
And the laptop screen model is: B156XW02 V.0
This is an LED backlit 15.6 inch screen that uses a single 40-pin LVDS connector to the motherboard.
Some Info/My Attempt:
I figure that from the datasheet about the screen, the LCD has a max Voltage of 3.6, and a max current of 400 mA (0.4 A) and the backlight has a max Voltage of 3.4 and typical forward current (no max listed) of 20 mA (Seems really low?). It also lists the LED power consumption at 4.4 Watts max, which leads me to believe if the Volts are at 3.4 max, the current would be 1.29 amps max?
It seems to me that the max Volts required is 3.6 and max current required is .4 A or 1.29 A (depending on what is correct)? Since the Pi can output 5V and .5 A from the micro USB out (after the hub), or 5V and 2A from a special PiHat, I would say this  is feasible.
My question to you fine folks is: Will my idea work? If not, where does this breakdown, and can I add anything to make this work?


texts: Transistor current limit circuit - power handling?

texts:
I am designing a simple current limiter, which charges a large (4.7mF) capacitor with a charge current of (roughly) 500mA from a supply voltage from about 10-20V - see the below circuit.

My dilemma is that I already have a bunch of MMBT2222A and it would be nice to use this part without another line item.  Whilst it can happily push 500mA through the collector, it only has a power rating of 350mW, which will be massively exceeded when the capacitor is first charged as the voltage across the collector will be about 10V and hence the power will be about 5W for the first 200ms or so.
In the circuit above, I have added an extra 2N2222A in parallel (with the idea of adding more as required) with the existing one, but I feel this strategy if fraught with danger - mismatched gains will cause unequal currents and defeat the whole purpose of the exercise.
So, is there a clever way to achieve this circuit? Or, do I just have to bite my tongue and put a transistor in place with a better power rating?


texts: Deliberate Shoot-Through in H-bridge for EMI reduction

texts:
today I was analysing an H-bridge driver circuit in a commercial product which is used to drive a DC motor (approx 24V/4A) over an unshielded cable with about 1.5m length. When I did a simulation of the H-bridge I saw that shoot-through appears in every switching cycle. Even though the current waveform shows high spikes, the node voltage is rising and falling extremely smooth. This seems to be quite logical because you never have a reverse recovery overshoot of a clamping body diode.

For me it looks very difficult to surely stay withing the MOSFETs SOA considering all the device tolerances (driver is discrete), variation of threshold voltage vs. temperature and so on. The only thing to limit the current seems to be the long trace of the supply line (~50mOhm an a few nanoH), the ESR of the Elko and a small fuse.

Is this a good design practice or has anyone of you ever seen this approach to reduce dv/dt-induced EMI?


texts: N-channel jfet fixed bias with high gain = 200

texts:
simulate this circuit – Schematic created using CircuitLab

I would like to know if it is possible to produce an n-channel jfet connected in fixed bias configuration with a high gain of 200. If so, can you please give me a part number or a circuit diagram? The criteria are as follows:

Amplifier type:FET n-channel
Configuration: Common source fixed biasing
frequency range:100Hz-1MHz
Input signal:35mV,Rs=2kohm
midband gain:200


texts: How to protect a microcontroller analog pin from continuous overvoltage?

texts:
I have one design requirement where I have to acquire an Analog signal and read the same via a micro-controller.

I am using a normal resistor based voltage divider with values of 47K & 10K followed by a R-C Low Pass Filter.

It works fine but as the micro-controller can withstand a maximum of 4V at its input (Using a STM32 uC), I need to protect the pin in case the input to the divider is above 23V.

I connected a series resistor and 4V zener diode circuit at the output of the resistor divider to do so but it affects the linearity of the circuit.

For example, if input to uC is Vout and input to resistor divider is Vin then for case when resistor + zener circuit is not connected, the ratio (Vin/Vout) for entire range of Vin remains constant.
So ideally Vin can be calculated with the formula of Vin = 5.7*Vout

However, when zener is connected, the ratio doesn't remain constant and keeps fluctuating throughout the range of Vin and thus Vout data cannot be used to calculate Vin accurately.

I need to protect the pin from continuous over-voltage and transient spikes.

Can anyone suggest what should I do exactly to achieve required protection and linearity in circuit performance?


texts: Need help wiring a power supply to UK rocker switch

texts:
I'm looking to wire up the UK rocker switch/plug to a power supply. There's a black cable coming from the live & a red one coming from Neutral. I don't want to blow anything up so I'm looking for some help if someone can help me map which cables need to go where.
This is the power supply : https://gyazo.com/d00cdca931641a1a186160659f786d92?token=5072c9b33dbdfb7521bb23f5928c5532
Link to the actual product too: www.aliexpress.com/item/32823738256.html
This is the rocker switch: https://gyazo.com/e9845e141a03c70d48ffc3660ae8b625 (front) & https://gyazo.com/d0aa7ef9711a9f78e43e238af10bea7f (back)


texts: What is MECL 10h or 100 K ECL logic levels and how do I use them?

texts:
I was reading the comments to this question Can I replace a PLL Charge Pump with an Active LPF? and started looking at the MCH12140 and MC10EL07 that markrages♦ recommended.

When I look at the datasheet it talks about MECL 10h and 1000 K ECL logic levels. What does that mean? How can I use it?

Note, I did try to google what the MECL and ECL was, but either I wasn't using good search terms or it is just hard to find. There is pages on them, but nothing talks about 10h and 1000 k. I also don't really understand what the pages mean.

Also note that I have used TTL before, is there any comparison to TTL or a way to convert to it?


texts: How would I software-decode this 260KHz serial stream?

texts:
I've probed this serial stream coming out of a scoreboard controller and it seems like a proprietary protocol. How would I go about trying to software-decode this?

The start bit is 7.8us long. All the data bits are about 3.85us, giving a bus speed of around 260KHz. A logic HIGH bit starts with a 3.1us HIGH period then a ~800ns LOW. A logic LOW bit is the same but the periods are switched. Each packet is made of 255 bits, so about one packet is sent every millisecond.

I've thought of triggering on the rising edge and then reading the pin level after a short delay, but I don't think an interrupt-driven scheme would work that well because of the overhead.

Any ideas?


texts: Buzzer not working with delay avr atmega162

texts:
Hi I have got a problem that will be simple to you guys but i am newbie so its difficult for me to get things done correctly,

I Have buzzer interfaced with PinC0 of atmega162 , with crystal 12MHz
Problem is that Its not producing beep with delays.

#define F_CPU 12000000UL
#include<avr/io.h>
#include<util/delay.h>

int main(void)
{
DDRC |= 1<<PINC0;
PORTC |= 1<<PINC0;
while(1){
PORTC ^=1<<PINC0;
_delay_ms(1000);
}
}

Buzzer is connected on PINc0 and then grounded on another end.
its just a common buzzer.I dont know its model or datasheet

Every thing was working fine some days before I don't exactly know what happened all of sudden.

Proteus Simulation is working correct but realtime is producing long beep in slow voice with no delays

Awaiting for your appraising replies. :)


texts: Sawtooth Wave Fourier Series- MATLAB issue

texts:
I have what I believe is the correct equation for my sawtooth wave

However, I am having issues with representing it in MATLAB. I keep receiving an error message saying
"Matrix dimensions must agree.
Error in problem1_plot (line 7)
basis = ((-1).^k).exp(jpi*k.*t);"

I tried looking at each part of the basis, and it seems the problem lies within the exp term. When I tried to run my code with only that part of the basis in, the same error message popped up.
I'd appreciate any help in clarifying what the cause of this issue is.

t = linspace(0, 5);
k = -100:100;
x = (2*j)./(pi*k);

xm = repmat(X ,[1, length(t)]);

basis = ((-1).^k).*exp(j*pi*k.*t);
x100 = sum(xm.*basis);

tmin = min(t);
tmax = max(t);

plot(t,x100);


texts: BeagleBone Black reboots when connected with HDMI Display

texts:
I am working on BeagleBone Black board (Debian running on it) and it is working fine. Now I want it's Linux GUI on screen, to do so I have connected BeagleBone Black with HDMI cable.

Now, when I power it up it displays boot log messages on screen but after displaying logs it automatically reboots.But if I am connecting HDMI display to BeagleBone Black after boot process is complete it works fine. It reboots when HDMI display is connected to it while powering it on.

I am using 5V-1A power supply as prescribed in Documentation of board.

I am unable understand why I am facing this issue and how to resolve it.


texts: Can two Ethernet PHY chips be connected directly through SGMII MAC (without going through MAC chip)?

texts:
I need to design something like a media converter: copper interface converts to another copper interface or to SFP optical.

I want to use two of Marvell's PHY chips, which will be directly connected through SGMII MAC interface (without any MAC side host).  But I'm worrying about this direct SGMII MAC connection. Is this correct? Will this work?

simulate this circuit – Schematic created using CircuitLab


texts:
The displayport protocol runs at a fixed frequency of either 1.62GHz, 2.7GHz, or 5.4GHz. The pixel stream (strm_clk) it carries runs at an arbitrary frequency and is likely to be asynchronous to the link clock (link_clk). The receiver is supposed to recover strm_clk from two numbers M,N, as their ratio, i.e., strm_clk/link_clk = M/N, where N is fixed to 32,768 and M depends on how many strm_clk cycles have been recorded during N link_clk cycles. In asynchronous mode, we would expect M to slightly vary in time. So far so good.

Now, the problems:

M,N are sent once per frame, whereas they are reset every N=32,768 link_clk cycles which is in about 2-3 lines. How can the delicate changes in M be detected by the receiver who doesn't see M as often (only once in millions link_clk - during the vertical blanking)?
the lowest 8 bits of M are sent every line - which may explain the above, but since M is reset every N=32,768 link_clk cycles, so are its lower 8 bits, which will undermine the ability to use these bits as a reference between two clocks (due to what appears as sudden resets on these bits). How does that work - are there two separate counters?
another (minor) issue: in every stream clock, 24 bits are sent (in RGB 444 mode), the displayport sends either 4 or 8 bytes (depending on the number of lanes / their speed). Does that mean that in every lstrm_clk cycle, M should increment in a fractional manner (i.e., by 3, by 3, then by 2)?

I find the standard hard to understand - basically, page 60 here:

http://read.pudn.com/downloads98/sourcecode/others/400577/DportV1.pdf

Bottomline: can anyone explain how this N,M scheme is supposed to work given the issues above?

Any thought would be highly-appreciated!


texts: LTC1707 Buck regulator Vout signal ground confusion

texts: I am using the LTC1707 buck regulator to step down from ~6V (4 aa alkaline cells) to 5V. I am confused about proper grounding. Initially I used a common ground and this caused Vout to be 6V when Vin was 6V so I knew I did something wrong. Then I re-read the datasheet PC board layout checklist where it mentioned segregating signal and power grounds. I probed Vout and R4 and sure enough it showed 5V. I did this on a breadboard but now I'm going to solder it more permanently. Should I be using this point on the resistive divider (R4 lead) to ground the rest of the circuit that will be using the 5V Vout? Also I'm unsure about the star ground formation. I gather it's when a single point connects the ground planes. So Since R3 is connected to power ground does this complete the star ground formation?


texts: Current Sensing with uController and Op-amp

texts:
The circuit i have drawn is to sense currents of a Target uController operating at 3.3V. to see how it operates in sleep and normal operation. This information is then sent to the Interface uController ADC to log the current. Both circuits operate at 3.3V

I have drawn this circuit up so i can sense currents between nA to 450mA by manually switching the resistors in my shunt circuit and then using a precision op amp (MAX4239ASA+) to amplify the sensed voltage.

So the way i get the current range is by using 3 separate resistors.

0.01R for 1-450mA
10R for 1-100uA
10K for 1-100nA

The questions i have are:

Does the idea of this circuit work?
I am worried about people switching to the nA range and then there being a larger current drawn and thus blowing the circuit.
Would i require some sort of fuse or current limiting on each resistor leg? But then i feel this would alter the precise resistance of the leg.
Need help understanding what precision of current i would get for each resistance leg if the ADC is 10-Bits at 3.3V?
Is there any way to automate the switching of these resistors, almost a dynamic range? But i feel this would be dangerous.

Thanks, if anything else should be added or advice on a different op amp all is well!


texts: Altium VersionControl_RevNumber special string

texts: I have encountered a rather strange problem in Altium Designer 17.1. I am using the special strings VersionControl_RevNumber and VersionControl_ProjFolderRevNumber to keep track of our PCB Revisions as we are cutting new boards about every two weeks due to some pretty crazy scope changes in the project. All other special strings are converting fine, but the version control specific special strings have stopped functioning out of the blue. Has anyone else experienced this? Is there a work around? I havent had any luck on Altium Live. I am using the internal Altium SVN. This was functional in 17.0 and 17.1 for at least three revisions of the pcb, so it seems unrelated to the similar bugs on Altium Live. This most likely is a project configuration problem, but I do not know where to look.


texts:
While reading "Electronics for dummies" went through the following block and I realised that I have some uncleared concepts about electricity:

  Electrostatic discharge involves very high voltages at extremely low
  currents. Combing your hair on a dry day can develop tens of thousands
  of volts of static electricity, but the current is almost so
  negligible you seldom notice it. The low current prevents the static
  discharge from really hurting you when you receive a shock. Instead,
  you just get an annoying tickle

I thought that voltage is the driving force that drives current, and the magnitude of generated current depends upon the resistance attached between terminals of a voltage difference, if so then why is there a low current generated by tens of thousands of volts of static electricity? if 220 volts in socket can electrocute then why not this tens of thousands of volt can? the resistance is the same i.e. the body


texts: Unconventional TEC peltier use (heating)

texts: I'm going to be breeding reptiles, so I'll need an incubator. I'm currently thinking about using tec coolers as a heater inside an insulated box. The issue I'm thinking I'll have is that with a cheap o controller with a probe like this one https://www.ebay.com/itm/223951905414 I may blow up something using a 3x 40mm 12v 6amp tec chip setup and two separate power supplies to reverse polarity. If there is an easier way to do this, that'd be great. All I need to do is get the air in the space to be warmed/cooled to 90 degrees f. Thanks for your time!


texts:
I'm making a simple op amp circuit to use it as a compactor.

I connect the non-inverting point to a simple circuit and the inverting to a 3 volt dc supply.

the circuit should compare the voltage at the non-inverting terminal with the 3 volt.

Actually the circuit is working very well . But, when  I change the value of R1 and R2 to 500 M ohm the circuit goes crazy .The voltage at the point between R1 and R2 is no longer 2 volt it changes to 2.4 volt

I know that the high value of the resistance made that.

What should I do to solve this problem and make the circuit works well at 500 M ohm.


texts:
I have a capacitor with 3 pins + 4 for assembly(common ground?).
It is paired and I found it in an old (tube/valve amplifier) TV.

I couldn't find any docs about it.

It has written on it:

Tesla TC 448

{circle} - 200uF 350V

{square} - 100uF 350V

{triangle} - 50uF 350V

What do these mean? How do I have to connect it to my circuit to reach the capacitance I want?


texts: What is to be used to switch the load: Relay or MOSFET?

texts:
I have a circuit that requires to switch on/off the load using arduino control signal. The load uses 5V DC and upto 3A current. MOSFET or relay must be used to switch the load supply on/off. Input to my circuit is continuous 5V DC.
Which should I use either a relay or MOSFET?
I have used IRF540 MOSFET which works but after it switches on the load voltage is only 3V, which is very less power to the load.
If I have to use a MOSFET what type of MOSFET is preferrable?


texts: When IO is limited on a uC, how do you move the logic away from the uC?

texts: For instance, if you had an Arduino with 4 digital IO pins, how could you independently light > 4 LEDs, or read the state of > 4 buttons?


texts: High Pass Filter Design from Transfer Function

texts:
I need to design a circuit that implements the following transfer function:

\$G(s)= G\frac{s+z}{s+p}\$

where, G = gain, p = pole and z = zero.


texts: DC disconnector/breaker and battery fuses for 24V 100Ah solar system

texts:
I have an off-grid solar system up and running well so far. However, as far as understand there is one essential part is missing in the setup which is the DC disconnector between the inverter and the batteries. I need an advice on what kind of DC disconnector/breaker and battery fuses I should use. I often see many notes advices on NH00 but wanted to make sure what I am doing is appropriate for my particular setup. The links to ebay or amazon would be lovely.

My current setup:

INVERTER

50A PWM - Sorotec Solar Hybrid Inverter SSP3118C 3K
24V

BATTERY

2 x 12V 100Ah - Vision AGM GEL CG12-100XA (Wired in series to get 24V)

CABLE

4mm diameter copper cable has been used


texts: Step/Dir input Servo Drive: how does it work internally compared to a serial input drive

texts:
I believe that the most common type of servo drives are based on STEP/Direction input which is inherited from the Stepper motor controllers.

My question is how does the type of controller work internally ?

My Logic says : the step input is connected to a "timer" in counter mode inside the micro controller and based on direction input the up/down counting is chosen automatically . this number is then subtracted from a Encoder pulse counter and the difference is fed into a PID loop .. is this correct ??

if this is correct, does its performance differ from a servo drive that uses serial interface to get the required position directly ? the main concern is motion planning because in such drive you are not feeding the steps slowly at start and stop to control the acceleration and deceleration ?


texts:
I'm currently repairing a project built by someone else and want to avoid tinkering with it as much as possible.

I am looking to recharge 3 AA NiMH batteries (at 1.2v each), that are in series.
I understand that it's difficult to charge in series, and that I should have some sort of regulator in order to not completely destroy the batteries. However, I'm short on time and money right now.

Could I simply use a 3.6v (or higher) DC charger to recharge the batteries?

Thanks!


texts: Dead reckoning with accelerometer & gyro. Possible?

texts:
I have a 3 axis accelerometer and a 3 axis gyroscope. I've been tasked with developing a dead reckoning system using this hardware.

Essentially what's needed is for me to develop some code to track the position in 3d space of the board in real time. So if I start with the board on a table and lift it 1m upward, I should be able to see that movement on the screen. Rotations need to be taken into account too, so if I turn the board upside down half way through the same movement, it should still show the same 1m upward result. The same should also hold for any complex movement over a period of a few seconds.

Ignoring the maths needed to do calculate and rotate vectors etc, is this even possible with such a low cost device? As far as I can tell, I won't be able to remove gravity with 100% precision, which means my angle relative to the ground will be off, which means my vector rotations will be off, which leads to an incorrect position measurement.

I also have noise from the accelerometer and gyro bias to account for.

Can this be done?


texts: Testing a 24V 40W LED lamp with constant current LED driver

texts:
I am trying to test a LED lamp of 24V and 40W with the driver HLG-40H-24B (constant current, output 24V and 40W) but it does not work correctly: The LEDs flash regardless of the voltage value (from 1V to 10V) that is applied in the DIMMING input of the driver.

In RS-Online, I found this document (A guide to buying LED drivers) where it explains that for a LED driver of constant current, it is necessary to choose one with a higher output voltage than the LED lamp (page 4). Is this why the LEDs are blinking? If so, what output voltage and output power should the constant current LED driver have to drive this 24V and 40W LED lamp? Thanks in advance.


texts: Does this circuit convert sinewaves to square waves?

texts:
As part of a graded assignment on diodes, I was given this question.

I ended up designing this circuit :-

simulate this circuit – Schematic created using CircuitLab

However, I only got partial credit for the circuit. The official solution was :-

With each of the zener diodes having a breakdown voltage of \$2.5\,\text{V}\$.
I want to ask before I challenge the grading. Will my circuit also work?


texts:
I am new with electrical and want to install motor on my bike. I want to know how volt and watt are related in DC motor and how can they help me choose the right battery pack.
If I have 1kW motor but I am not sure how much battery I needed and what will affect the speed and duration of motor.
I have seen 1kW motor with 36V and 48V. How these both are different and which one should I choose for work and if choose anyone then what battery pack do I need?
Help me with that


texts:
I am trying to use lock bits for protection on atmega32.I am not being able to write lock bits to it its giving me verification error while doing it.Can you tell me correct way to do this?

This is the error I am getting while programing:


texts: What is the name of this circuit in English?

texts:
I hope that this is the right place to ask this question. English isn't my first language. So here is my question. If you are familiar with analog circuits you know about power amplifier. Here is simple schematic.

(source: gpstronic.com)
So there are 2 steps in the power amplifier the first one amplifies the voltage(U) and the second one the current(I). Whats the name of the second step. In my language we call this final step with/without transformer but when I search for this in WWW I don't find anything. I will be very grateful if somebody answer to my question.


texts: Why there is a different number of turns? Why there is not 8 turns on each side?


texts: Nodal analysis for dependent voltage source

texts:
I want to apply nodal analysis at the red marked node of the above circuit.  Here is my equation :

$$0.2v_0 - i_0 - 5 + \frac{v_3}{40} + \frac{v_3 - v_2}{10} = 0$$

My equation includes a supernode formed due to the dependent voltage source $$4v_0$$

Is my equation correct for nodal analysis?


texts: Is it possible to only fill a Li-ion BMS partially?

texts:
I'm putting together an 18650 battery pack for an e-bike. The BMS is specified for 10s 36v 40a.

Is it possible to use the BMS with only, say, 2 or 3 of the 36v packs of cells I made? The use case would be for a lower capacity pack.

Edit: Removed part of question after clarification about proper BMS wiring.


texts: SystemVerilog Assertions syntax error unexpected |->

texts:
I'm starting to use SVAs for formal verification.
I run QuestaSim2019 and I can successfully import uvm_pkg (is it needed to use assertions anyways?):
as I do import uvm_pkg::*; I get # -- Importing package mtiUvm.uvm_pkg (uvm-1.1d Built-it).
Following this guide I wrote my assertion:
property p_prop_name;
     @(posedge clk) disable iff (!sig1 && sig2) |-> sig3;
   endproperty

   a_assertion_name: assert property(p_prop_name);

As I tri to compile using vlog I get the following error:

** Error: (vlog-13069) sva/compx_sva.sv(34): near "|->": syntax error, unexpected |-> .

I checked the syntax and to me it looks alright. Any ideas why this should not work?


texts: Zener diode level conversion of tristate output

texts:
I have an MCP73831 li-ion charger connected to an ATMega1284p. The charger has a tri-state status pin which can be High(5V), Hi-Z or Low. The ATMega runs at 3V3.

I want to be able to read the value of the tri-state. I don't need to discern between Hi-Z and High. I was thinking of using a 1.8V zener like so:

simulate this circuit – Schematic created using CircuitLab

Will this work? And what do I need to be aware of?


texts: Recording multiple pixels simultaneously in CMOS or CCD image sensors

texts:
Is it possible to recording multiple pixels simultaneously in CMOS or CCD image sensors?
Because of the low intensity of radiation I need to increase the surface area of the each pixel (photodetector).
Is it possible that data of 4 or 16 pixels will be measured at the same time and sum together?
For example, a 1024 * 1024 pixel image sensor with 10 * 10 micron pixel area is worked similar to a 512 * 512 pixel image sensor with 20 * 20 micron pixel area.


texts:
I would like to build a software interface using the usb4java library, for sending triggers for synchronization with the following specifications:

Latency below 1 ms
Range: 8-bit [0, 255] + bit [0, 1]
On the receiving end the bits will be translated to strings (e.g. "S255" or "R128")

I have the following concerns:

For two computers with USB 2.0 ports to be connected with a 3m cable, what cable should I use - bridged or unbridged A/A?
Should I be concerned about risks for short circuiting or otherwise permanent damage to the hardware?
Will a universal USB driver suffice?
What USB device class does a direct PC-PC connection classify as?

Note: I have no prior experience of hardware programming.


texts:
I'm completely new in hobby electronics, and I assembled the following circuit to control a power LED over wifi using esp8266. The problem is, that it is always, on no matter, what I send via GPIO1 port. I know that this is not an esp8266 problem, I tested my program with a simple low power LED, without the NPN transistor. I'm sure, I do something wrong with connecting that transistor.

simulate this circuit – Schematic created using CircuitLab


texts: What types of cables do ferrite beads/chokes have a beneficial effect on?

texts:
Ferrite beads prevent electromagnetic interference from affecting a cable. Without fundamentally understanding how EMI works, this is obviously a beneficial effect for the stability and integrity of electronic devices.
However, commercial cables have very inconsistent configurations regarding ferrite beads:
Many Serial/VGA and DVI cables have ferrite beads attached to both ends. However, very few HDMI and DisplayPort cables have any ferrite beads, although they can transmit more signals of different types (video/audio/ehternet).
On USB cables, it's rare to find a Micro-USB cable of any length with a ferrite bead, while sometimes even short Standard- and Mini-B cables are rather common to have one or two attached to them, even though all connectors have exact same data and power specifications.
I have also seen a lot of older PC cases which have a ferrite ring around the front-panel cables (just LEDs and power switches), while I've never seen newer cases with any such rings or on any outlet power cables, however some laptop power supplies have one on the device end.
Finally, I have never seen an ethernet cable with a ferrite bead, although they can transmit both data and power over long distances and are very delicate in regard to signal quality (categories, twisted pairs, shielding and so on).
So, this makes me wonder:

What kinds of singals ferrite beads have an effect on: Just analog, data cables, power cables, all or none ("snake oil")?
How great the effect is on the cable (this will likely depend on the environment)?
Whether cable length is important (since no 50m ethernet cable has them, but 10cm USB cables do)?
Whether cable gauge is of any importance?
If there can be any adverse effects of using a cable with a ferrite bead (as it increases the impedance)?
Are two beads always "better" than one?

Background of the question:

 We have a bag full of aftermarket ferrite beads at work and I'm considering if it's a good idea to use them on cables that run close to big lighting and sound equipment. Although there were never any apparent signal issues, stability is of the highest priority and adding the beads would cost nothing.


texts: Why is breakthrough voltage of a TVS-diode decreasing when in parallel with an inductance

texts:
in our lab we are testing a circuit which has an inductance and a TVS-Diode in parallel. The task is it to determine the breakthrough voltage of the diode.

The test works like this:
We apply a voltage of 24V to the circuit and then instantly switch off the supply voltage via a relay. We then measure the induced voltage of the circuit. You can see the voltage in the picture below.

My Question now is: Why is the cut-off not horizontal (for example constant -48V). Instead you can see a change in voltage from -50V to -48V.
We assume that the time response of the diode has something to do with it.

The TVS-Diode used is this one: http://www.vishay.com/docs/88301/15ke.pdf.

I hope someone can elaborate on the phenomenon.
Thank you in advance.
ELWI


texts: Please explain about the red dots in the below picture

texts: I saw the picture some where and wondering if the red dots are buried vias or test points


texts: solving for bias currents in non ideal op amp

texts:
I am trying to work with the non ideal model of the op amp and solve for the dc output voltage in terms of the bias currents while ignoring input offset voltage using the following schematic

simulate this circuit – Schematic created using CircuitLab

Using superposition I control IB1, and get that I1=IB1+\$\frac{Vodc1}{R2}\$ where IB1=\$\frac{Vodc1}{R1}\$, but I can't quite get the entire output voltage in terms of IB1.
Also, when I solve for the second current source IB2, I get the situation where there is a current source from ground to ground, which means no current, and therefore IB2=0, so I2=\$\frac{Vodc2}{R2}\$
It seems like I'm missing something here because my resultant d.c voltage is
R2(I1-IB1+I2), which isn't really entirely expressed in terms of biased currents like I wanted it to be.
What am I missing here?


texts: Why are LEDs in my home unaffected by voltage drop?

texts:
As a result of heavy snowfall yesterday night, I woke up to find out that the regular 230 volts delivered to my house had dropped to 110 volts (fixed later that day by the power company). Old fashioned light bulbs worked as if a dimmer was attached to them (only a little light), fluorescent lights did not work, one LED was blinking while the remaining LEDs worked fine!

Why is it that LED lights were unaffected by the storm, while all the other lights were affected? The LEDs were regular E27 socket LED light "bulbs".


texts: Buck Converter Supplying Boost Converter - Potential Problems?

texts:
This post asked a similar question to mine, but the problems that I have noticed are distinctly different.
I have a PCB that uses a buck converter to supply 12V from a 24V source, and I am boosting the 12V to 36V. The boost converter works well on its own from a power supply's 12V (150mA), but only outputs 12V (4.32mA) when supplied with the output of the buck converter.
Why might the boost converter be working incorrectly when supplied from the buck converter?
The buck converter should be able to supply up to 3A, and when a 68 Ohm resistor is connected 170mA are seen through the resistor.
When a 1 Ohm resistor is put between the converters, the characteristics worsen - more current drawn, output voltage of boost converter reduced.
I'm sure that the 24V source would have been sufficient to boost to 36V but no appropriate parts were found for this function.
Are there any other investigative steps I should make to ascertain the source of the issue?
The buck converter is connected as seen in the following schematic, where Vin is 24V.

The boost converter is connected using Cin=220uF, Cout=100uF, Ctune=10nF, Rtune=30.1kOhm, Rtrim=6.98kOhm


texts:
I want to make kind of autonomous power supply for my RPi.

So that I am planning to use 12V solar cell and batteries for this project.

Also I will use Arduino to controll all of this stuff - to monitor the voltage both of solar cell and battery and to switch power destribution.

I suggest 3 working states:

Battery low - solar cell charges battery and powers up RPi
Battery full - solar cell powers up RPi only
Solar cell low - battery powers up RPi

This is the exemplary scheme

The idea is to measure voltage both of solar cell and the battery and implement simple logics to switch power destribution unit and to charge battery if it is low.

Btw I don't want to use any power bank because there is no built in interface for reading remaining charge.

It would be great if you recommend me solar cell and battery setup/assembly for this purpose and correct my scheme.

This is the preliminary list of items:

5V regulator
switch
batteries
solar cell
battery charger module

Any advice will be appreciated, thanks!


texts: 3 Phase Dyn5 transformer neutral groundig

texts: What happens when a Dyn transformer grounding fails? The transformer has mixed loads (1phase, 3phase) also unbalanced. It is going to act as an isolation transformer or ...? Will the phase and line voltages remain the same?


texts:
I'm doing a school project in which I need to measure the amount of light emitted by a specific object.

The first thing that came to my mind was to use a photo resistor hooked up to a voltage meter in resistance mode. After some research on the internet, it seems like photo resistors are not extremely accurate.

My question is exactly how accurate a photo resistor is against itself. I will be using the same one throughout the whole experiment, and would like to detect small changes with different light sources.


texts:
I am making a robot for my workplace right now.  I started with a 20servo kit.  It came with a really terrible 10.6volt, 800mAh NiMh battery pack though.

I would like to make a lithium pack for this since 3 lithium cells would be perfect.  I use LiPo for my personal model airplanes and I know they are "balanced" and they use special chargers that charge each cell independently.

Since this is for my workplace I do not want to use LiPo because they are so volatile.  I was thinking of making my battery pack out of 3x RCR123's.  I would like to make the pack so it can be charged with a balancing charger.

Can someone please tell me how to do this?  Also, can I use a LiPo charger for Li-Ion or do I need to make my own charger?

Thank you.


texts: Why Schottky diode’s cut in voltage is less and the reverse saturation current is more than normal P-N junction diode?

texts: I want to know how do we achieve lower forward voltage as much as 0.2-0.3 volt in schottky diodes.


texts: Power switch: leaving battery connected at one terminal

texts:
Just wondering if there is any real-world practical difference between a power switch that disconnects both terminals of a battery vs a switch that just disconnects one terminal.

Are there any possible consequences for leaving the negative terminal of a battery always connected to earth, it terms of battery lifetime or self discharge?

Will a battery that's fully disconnected at both terminals maintain its charge for longer?

Which approach is taken in real world consumer devices?


texts:
I'm wanting to build a system that will store value on a SD card to form .CSV file , that this is not a problem. There will be about 1000 value recorded daily.I'm wanting to send this values to a pc daily and i want use of two gsm modem for this task . can doing this task with two gsm modem or no?

What other methods are recommended? Or how can this be achieved?do FTP is better option for upload data on host and then download on pc?

Thanks in advance!