texts: STM32F429 CANopen with or without transceiver

texts:
this might be a stupid question but i'm unable to clarify this by myself.
So i'm working on a project with a STM32F429zit microcontroller.
I would like to use CANopen in my project so i can communicate with other CANopen devices. From what i know now is that CANopen is a layer written on top of the CAN protocol. So it uses the same hardware. My microcontroller has 2 CAN interfaces, i've seen a video on youtube( https://www.youtube.com/watch?v=GYhsHJi6pKE&t=357s ) from a guy connecting two STM32F429 boards to each other via CAN directly. I've also seen a movie from a guy using three STM32F429 boards and connect them all together via CAN with a MCP2551 transceiver( https://www.youtube.com/watch?v=4fYoXGiIdDs ). Could somebody explain me the difference between those two setups?
Is it really necessary to use an external transceiver to communicate over CAN?
I'm planning to communicate with touchscreens using CANopen, those screens are working on 12VDC.

I hope somebody can clarify this for me.

Thank you all!!


texts: Accuracy of a dac - INL rating how that relates to deviation in mV's

texts: In the datasheets of a dac they talk about the INL error. As I understand this is to do with how much the output of the dac deviates from the output of an ideal DAC. So I was wondering how does that translate to how much the voltage will deviate in mV's? I'm using a MCP4922. The datasheet say it can be as high as +/- 12LSB.


texts: How do external circuits in light switching units (such as Lightwave RF) use the mains wiring for power?

texts:
LightwaveRF is a simple switching unit that contains additional circuitry to enable automatic wireless switching. The additional circuit is powered by the mains light switching circuit.

This is my how (I think) a simple single way mains switching circuit works:

So there is a live and neutral present, but for an external circuit to make use of this supply, the mains circuit must be closed (so the bulb must be lit), right? If not, can you explain why? Can you explain how devices like LightwaveRF power their external circuit from an open mains circuit?

I'm sorry if this is a stupid question, I just cannot get my head around how these things work without closing the circuit and turning the lighting on.


texts: Circuit with both common source & common gate

texts:
I'm trying to calculate the following cirucit's voltage amplification \$A_v= \frac{V_{out2}}{V_{s2}}\$ using the known topologies of common source & common gate.

On one hand, I can see that on the left there's a voltage divider with common emitter, which can result in \$A_v=\frac{R_{g1}}{R_{g1}+R_{g2}}\cdot \frac{-g_{m1}R_d}{1+g_{m1}(\frac{1}{g_{m2}}+R_s||R_L)} \$

But on the other hand the signal travels to the output through \$M_1\$'s source, in a common gate fashion, which I don't know how to take into account.

How should I analyze such a circuit?

Thank you.


texts: Why is a receiving circuit in e.g. RFID made resonant with a parallel capacitance instead of a series capacitance?

texts:
Take for example the schematic below of a inductive receiving circuit in RFID, where we want to maximize the voltage over the load resistor R4 (R3 is the resistance of the inductive coil, and the voltage source represents the signal that is received and induced in the coil)

simulate this circuit – Schematic created using CircuitLab

The voltage is now V2*R4/(R3+sL1+R4), which in my opinion can easily be maximized by adding a series resonant capacitance, such that the impedance is real at resonance (and further maximized by increasing R4). However, I read that voltage maximization for circuits as this one is done by adding a parallel capacitance. When doing the calculations, I always obtain a voltage that is lower than the one for the simple series resonant circuit I present here.

EDIT: when considering the measuring device to have an infinite input impedance, the measured voltage for the series resonant circuit equals the applied voltage V2. For the parallel resonant circuit, it equals 1/(sRC) times the applied voltage V2. Is it possible that the eventual best solution is depending on the size of R and C and the operating frequency (whether their product is larger or smaller than 1)?


texts: Can anyone enlighten me on how to approach this question? I had tried solving it for hours and still doesn't have a clue. The circuit is an overdamped circuit and required to find the parameters. Please help!


texts: What should be the sign of the voltage across the inductors while doing circuit analysis?

texts: I am not able to understand what should be the sign of the voltage across an inductor while doing circuit analysis. I know the voltage across an inductor is given by -Ldi/dt, when the rate of change of current is increasing,voltage is negative which means its opposing the direction of current and when rate of change current is decreasing,the voltage is positive which means voltage is along the direction of current. But in every book irrespective of the rate of change of current(increasing/decreasing),they are taking the voltage across the inductor to be positive(i.e. v=+Ldi/dt).I dont understand this.I dont think they have applied the same logic here.So would be very helpful if someone could exactly explain whats going on.


texts: Calculating the voltage drop in AC circuit

texts:
I'm supposed to calculate the voltage drop (Ux). Where R=R=R=1kΩ, C=1µF, I=1mA, E= 2sin(ωt+pi/2), ω = 10^3 rad/s.

I know I have to use superposition method, but I dont know how to calculate impedance in both situations.


texts: Reliably using motor at higher than normal voltage

texts:
I am making an ROV that uses Jameco DC Motors, and I use a 12 volt battery. I looked at the spec sheet for the motor, and found that the normal voltage to run these motors are 12v, but the operating range is from 6-18 volts. Does this mean I could use a boost converter to take my 12v battery, and set it to 18v, making the motors go reliably faster? I am not trying to blow up the motors, but I do want to make them faster if possible. I'm new to experimenting with these types of things, so sorry if this is a silly question or if it has been already answered (didn't know what to look up!). Thanks

jameco 232022
website: https://www.jameco.com/z/MS5N-1885-R-12-Volt-DC-Motor-740mA-9820-RPM_232022.html


texts:
I am struggling to find a real conversion formula for converting the RAW value into result that makes sense. I am using an OPT3001 sensor from TI and ATTiny25 as MUC.

I have found one example online, but it does not give the correct value in Lux, the equation used there is this:

/*Convert to LUX*/
//extract result & exponent data from raw readings
result = raw&0x0FFF;
exponent = (raw>>12)&0x000F;
lux=0.01*pow(2,eksponent)*result;

This gives wrong values according to my Lux meter that I have as refference and, for example, lux meter says its 420 lux inside Office.. the equation above gives me the result 110 Lux, which is not realistic. Sensor is working fine as I replaced it new one, in order to be 100% that it is not sensor related issue.

The result is very close if I taked only result = raw&0x0FFF; , but then it fails at higher values (when I put my sensor under the Lamp light bulb).

I do not think it's an error inside my I2C code, but I will attach here also the part of my coude for UpdateLight:

// I2C OPT address
#define OPT_ADDR_W  0x88
#define OPT_ADDR_R  0x89

// I2C OPT registers
#define OPT_RESULT_REG  0x00
#define OPT_CONFIG_REG  0x01

// OPT config bits - automatic full scale mode, 100 ms conversion, single-shot
#define OPT_CONFIGURATION_H 0xC2
#define OPT_CONFIGURATION_L 0x00

void UpdateLight(void)
{
    uint8_t error = 0;
    // start conversion
    I2C_Start();
    error |= I2C_Write(OPT_ADDR_W);
    error |= I2C_Write(OPT_CONFIG_REG);
    error |= I2C_Write(OPT_CONFIGURATION_H);
    error |= I2C_Write(OPT_CONFIGURATION_L);
    I2C_Stop();

    // wait for conversion
    _delay_ms(150);

    // set result register
    I2C_Start();
    error |= I2C_Write(OPT_ADDR_W);
    error |= I2C_Write(OPT_RESULT_REG);
    I2C_Stop();

    // read data and update scratchpad
    I2C_Start();
    error |= I2C_Write(OPT_ADDR_R);
    if (error == 0)
    {
        scratchpad[1] = I2C_Read(1);
        scratchpad[0] = I2C_Read(0);
    }
    else
    {
        // report error value
        scratchpad[1] = 0xFF;
        scratchpad[0] = 0xFF;
    }
    I2C_Stop();
    }

And this is my old formula that I came up with, but it gives even more ridiculous results than the above one from the internet:

   // calculate light ( LUX = (MANTISA << EXPONENT) / 100 )
   light = (int16_t)((float)((uint32_t)((spad[SPAD_MSB] << 8) | spad[SPAD_LSB]) << (uint32_t)((spad[SPAD_MSB] >> 4) & 0x0F)) / (83865.60 / LIGHT_MULTIPLIER));
   debug_printf("L_RAW: %02X%02X\r\n", spad[SPAD_MSB], spad[SPAD_LSB]);
   debug_printf("L_VAL: %d\r\n", light);

Adding the output lines of the above print statements:

  L: 5460 - 824

  L: 5464 - 824

  L: 5462 - 824

  L: 5462 - 824

The first value should be RAW MSB and LSB, and the second is the converted value to Lux, using the formula above this.

Moreover, I am surprised that inside the Datasheet, TI did not provide a conversion formula ?

Any help is greatly appreaciated.


texts: How to code VHDL in one single .vhd file?

texts:
I am coding in vhdl and I want to have all my codes in one single file. Here is the code I have in one file (full adder and half adder):

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

use work.Single_Bit_Half_Adder;

entity Single_Bit_Full_Adder is
    Port (
            A :in STD_LOGIC;
            B :in STD_LOGIC;
          Cin :in STD_LOGIC;
          Sum :out STD_LOGIC;
          Cout :out STD_LOGIC
          );
end Single_Bit_Full_Adder;

architecture Behavioral of Single_Bit_Full_Adder is

component Single_Bit_Half_Adder is
    Port (
          A :in STD_LOGIC;
          B :in STD_LOGIC;
          Sum :out STD_LOGIC;
          Cout :out STD_LOGIC
          );
end component;
signal tempSum, tempCoutHA1, tempCoutHA2: STD_LOGIC;

begin

Half_Adder1: Single_Bit_Half_Adder port map (A => A, B => B, Sum => tempSum, Cout => tempCoutHA1);
Half_Adder2: Single_Bit_Half_Adder port map (A => tempSum, B => Cin, Sum => Sum, Cout => tempCoutHA2);
Cout <= tempCoutHA1 or tempCoutHA2;

end Behavioral;
------------------------------

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity Single_Bit_Half_Adder is
    Port (
          A :in STD_LOGIC;
          B :in STD_LOGIC;
          Sum :out STD_LOGIC;
          Cout :out STD_LOGIC
          );
end Single_Bit_Half_Adder;

architecture Behavioral of Single_Bit_Half_Adder is

begin

Sum <= A xor B;
Cout <= A and B;

end Behavioral;

But, I am receiving an error on "use work.Single_Bit_Half_Adder;" saying that single_bit_half_adder is not in library .

What should I do to solve this problem?


texts: amplify the ac signal from fpga 3.3v to 5v with placing coupling capacitor at the input and output

texts: In the above schematic I have reduced my negative voltage in the op amp , so that I get output voltage from 0 to 5v, otherwise I am getting the voltage from negative side. please suggest me the right solution for this circuit. As I was confusing for a long period.as also ringing waveform is occuring. I need output waveform starting from 0 to 5V.(input is 3.3VAC)


texts: what are the things to keep in mind when interfacing two digital devices?

texts:
what are the things to keep in mind when interfacing two digital devices, e.g FPGA with a dual shock controller or CPLD with a PS/2 Mouse, Microcontroller with an FPGA, FPGA with an external RAM.

One thing we need to make sure of is that the voltage levels are compatible for simplex communications. The output voltage of transmitter is compatible with input voltage of reciever. But what about impedances on both sides and board skews? How are things different for duplex communication?

There are different types of logic families and different type of circuits that generate outputs and take inputs with open collector being one of them.

Putting it simply, when interfacing 2 digital circuits, what things besides voltage levels will you need to take into consideration such that the interface does not damage the devices and works correctly.


texts: Pulse width modulation for three phase voltage source inverter

texts:
I have found a block diagram which discribes implementation of a modulator for the three phase voltage source inverter. I am not sure whether I fully understand this implementation of the modulator. I have decided to simulate this implementation of modulator in Scilab Xcos.

The overview of the Xcos block diagram is below

The internal details of the PWM block are following

The Inverse Clarke transform block

The Pulse centering module block

The Comparator block

The Three phase voltage source inverter block details are following

The First sliding harmonic block details

When I started the simulation I was surprised that the amplitude of the first harmonic of the line voltage at the output of the inverter is determined by the module of the voltage space vector \$|U^*|\$. I expected that the module of the voltage space vector \$|U^*|\$ should determine the amplitude of the phase voltage instead.
Simulation results are on below given picture where

black trace  - line voltage
blue trace   - first harmonic of the line voltage
red trace    - phase voltage at the load
yellow trace - first harmonic of the phase voltage at the load

Please can anybody explain to me why the module of the voltage space vector \$|U^*|\$ determines amplitude of the first harmonic of the line voltage instead of amplitude of the first harmonic of the phase voltage of the load? Thanks in advance.


texts: Guidelines on branching of a PCI express signal

texts:
We have 3 PCIe slots on a board, let's call them A, B and C. On this board, slot A will always be populated with a PCIe device, however, among slots B and C, only one of them will be populated.

There is only one PCIe link on slot A. So, in order to communicate via PCIe with either slot B or slot C, the same PCIe TXP/RXP/TXN/RXN signal on slot A should be routed to both slot B and slot C.

I don't know if this would be considered a common scenario. Probably not. I haven't been able to find out any layout guidelines covering this particular case.

Any ideas would be appreciated.


texts: Is it possible that the phases of the moon could have an effect on the operation of certain types of electronics?

texts:
What type, what could the potential effects be, and why would this happen?

EDIT: Yes, I am talking about physics not the supernatural. I figured this would be obvious unless people thought I was joking around, the tides are effected I know that much so obviously there is something physical going on here and I know some electronics can be very sensitive at very 'small' levels (not sure if 'small' is there word I am looking for here).


texts:
Need some help with the connections of the potentiometer.

In the circuit example provided in the link, I'm connecting the potentiometer as a voltage divider and not a variable resistor right? So instead of just connecting 2 pins, the Vcc pin of the potentiometer is connected to pin 16 of the sg3525 chip, Gnd pin of the potentiometer to Gnd and the middle pin or output is connected to pin 2 of the sg3525 chip? Am I right about this?

Thanks.

http://imgur.com/a/R1qA9


texts: How does the output jump up to 7.5 volts when the switch is closed and opened again?

texts: Sorry if the question might sound dumb. In this circuit, when the switch is closed the output voltage drops to zero and then rapidly charges back up to 5 volts. My question being, when the switch is opened up back again, the voltage spikes up to 7.5 bolts as shown in the oscilloscope figure attached. I am confused as the direction of the current would be the opposite of what it used to be when the switch is closed. Can anyone help me with understanding the behavior of this circuit? thanks!


texts: What's wrong with my IR21531D H-bridge gate drive?

texts:
I'm new to here. I am recently making an H-bridge inverter with IR21531D (here is the data sheet). I connected them this way:

When I measure the Lo and Ho pin with passive probe and differential probe (I only have one differential probe), and I got this

I use the differential probe to measure the voltage between Ho and VS, and the Lo and Ho gate signal are overlapped. The dead time is too large which is not even close to the datasheet (0.6 us typ.). If I connect my FET, the circuit will short together.

Can any master here could help me out? Thank you.


texts:
I'm trying to understand how the battery simulator circuit described in the Linear Technologies Application Note 58 works. Its schematic diagram from Appendix B, page 35 is below.

The application note starts the circuit description (about its charging mode - which is what I'm interested in) with this:

  In charge mode, current is forced through the battery input terminals.

From this I assume that the battery charger behaves like a constant current source pushing, say, 250mA (C/10 for my cells) into the (+) battery terminal on the upper-left corner of the schematic.

The note then goes on:

  The low voltage that develops across R8 is amplified by U1 and causes Q1 to shunt the charge current while maintaining the power supply PS1 voltage. U2, L1, CR1, C3 and C4 produce housekeeping 12V that is required to operate U1 and drive Q1. The power supply range is 1.5V to 15V. Q1 requires a heat sink. R1 is used for measuring the charge current. R10 and C5 simulate the AC characteristics of the battery.

That's what's puzzling me: how does a voltage develop across R8?

According to Ohm's law, for a voltage to develop across R8, there must be a current flowing through it, which I assume is the one pushed by the charger being tested (the 250mA). But as far as I can tell, there is no path for that current to go through R8 as -

Q1 is still off;
That current can't go against PS1, can it?
The forced current of 250mA would generate 50V on R9 while the power supply PS1 would be set to, say, 2.5V, simulating two AA NiMH being charged in series.

What am I missing?


texts: What happens to I/O pins in Low Power Mode on MSP430

texts:
I'm reading the datasheet for the MSP430G2553 about the low power modes that the microcontroller has but it doesn't talk about what happens to the IO Ports when it enters low power modes. It only talks about the what happens to the clocks like so:

  • Active mode (AM)
  – All clocks are active

  • Low-power mode 0 (LPM0)
  – CPU is disabled
  – ACLK and SMCLK remain active, MCLK is disabled

  • Low-power mode 1 (LPM1)
  – CPU is disabled
  – ACLK and SMCLK remain active, MCLK is disabled
  – DCO's dc generator is disabled if DCO not used in active mode

  • Low-power mode 2 (LPM2)
  – CPU is disabled
  – MCLK and SMCLK are disabled
  – DCO's dc generator remains enabled
  – ACLK remains active

  • Low-power mode 3 (LPM3)
  – CPU is disabled
  – MCLK and SMCLK are disabled
  – DCO's dc generator is disabled
  – ACLK remains active

  • Low-power mode 4 (LPM4)
  - CPU is disabled
  - ACLK is disabled
  - MCLK and SMCLK are disabled DCO's dc generator is disabled Crystal oscillator is stopped

So what happens to the IO ports? Is it a given that they remain in the state before it enters the low power mode?


texts:
I have "repaired" a cnc power nad speed control board from yoocnc (china) and it worked fine for a day. the next day the spindle just started running as power was applied. the mosfet was shorted, the pwm signal is fine.

Schematic here: https://maher-ramblings.blogspot.no/2014/08/cnc-engraver-schematics-yoocnc-nt65-3x.html

On this board I have shorted R3 and R4 and removed R5. R4+3 was suprisingly in the 8Kohm range and must have blown R5 and the optocoupler, but they are not in use so I just dissabled it.

Initially the ne555 also didnt work and was replaced, along with the Q1(IRF740), I didnt have a IRF740 but i put in a IRZL44 as thats what i had and it should tolerate 12vg-s.

I also cannot see the purpose for D3 diode, so any enlightenment there would also be appreciated.


texts:
I am using an STM32F100xx MCU and I want to communicate via UART with a GPS module, specifically the A7 Thinker GPS
GPS Module with A7 Thinker from Aliexpress

This module, when a 9V battery is used, operates at 3.6 - 4.2V .

The UART pins of the STM32F100xx MCU are 5V tolerant. Can I use UART communication directly without level shifters to 3.3V?


texts:
believe is a current transformer from air ionizer can somebody help me tell me what this thing might do I think it turns 110 into something less
P48A14-c/t only markings I see on it without opening it up I know you don't know what the winding numbers are came out of an air ionizer. A really old one think it was called airozone


texts: How do I use an LF355N JFET op amp to boost 2.8Vpp from function generator to 5V logic level

texts:
I have a Mini DSO DS203 portable oscilloscope. It can generate sine, triangle, and square waveforms with a peak to peak voltage difference of 2.8V.  Desired frequency range is 0-200Hz.  Duty cycle is not important.

I wish to boost the square wave output of this function generator to a voltage level that can be interpreted by an Arduino as a HIGH on a digital input pin. Can I use a simple JFET op amp to boost the signal?

I also have access to a reference 5V signal on my breadboard.  Is it instead possible to use an NPN transistor to switch the 5V signal using the 2.8V input signal?

What is the best route?


texts:
This is the program for blinking Red LED on port P1.0 on MSP430 Launchpad

#include <msp430.h>
int main(void) {
    WDTCTL = WDTPW + WDTHOLD;       // Stop watchdog timer
    P1DIR |= 0x01;                  // Set P1.0 to output direction

    for(;;) {
        volatile unsigned int i;    // volatile to prevent optimization

        P1OUT ^= 0x01;              // Toggle P1.0 using exclusive-OR

        i = 4000;                   // SW Delay
        do i--;
        while(i != 0);
    }
}

This was working fine except lots of warnings similar to the following:

  Interrupt vector "COMPARATORA" does not have an interrupt handler
  routine.  lnk_msp430g2553.cmd /LEDBlinking    line 88 C/C++ Problem

I got some help from the IDE only: At least one of the ISR vector was detected to be un-initialzed.

When I added the following lines of code, the warnings disappeared.

/* Initialize non-used ISR vectors with a trap function */

#pragma vector=PORT2_VECTOR
#pragma vector=PORT1_VECTOR
#pragma vector=TIMER1_A1_VECTOR
#pragma vector=TIMER1_A0_VECTOR
#pragma vector=TIMER0_A1_VECTOR
#pragma vector=TIMER0_A0_VECTOR
#pragma vector=ADC10_VECTOR
#pragma vector=USCIAB0TX_VECTOR
#pragma vector=WDT_VECTOR
#pragma vector=USCIAB0RX_VECTOR
#pragma vector=NMI_VECTOR
#pragma vector=COMPARATORA_VECTOR

__interrupt void ISR_trap(void)
{

}

pragma I know is a compiler directive that tells to do something explicitly. But what exactly is happening here I am not able to understand. Also the function ISR_trap(void) doing here? When I removed this function, I saw again those warnings.


texts: How to estimate displacement error using accelerometer

texts: I am using an MPU6050 and performing a double integration to obtain displacement, and this is to be placed in a vehicle that will be subject to about 2.5g. I cannot test it now, but how is it possible to estimate the error that the accelerometer will give me? Is it possible to use SIMULINK or MATLAB? If yes, could someone give me some pointers?


texts: ESP32: How can I shorten wifi-connection time to AWS?

texts:
ESP32 is sending temperature and humidity data from sensors to AWS over wifi and it's working otherwise fine, but wifi-connection is "on" for about 20 seconds. I'd need to shorten the connection time to save battery.
Can it be done? How short I can get it, practically? Where can I find more info on how to do it?


texts: PCB hanging upside down in its enclosure

texts:
Would this be a problem in a moderately high vibrations / shocks environment (passenger car interior) ?

The screws are 1.8 mm thread diameter, 5 mm long, the PCB being some 90 x 60 mm with nothing too heavy hanging from it and. The screws are on its four corners.

EDIT

the PCB is rather sparsely populated, about half of it not being covered by components. There are some 5 signal THT resistors, about 10 THT caps, a MCU, a radio transmitter, a PCB trace antenna, 2 SMT coils and 2 SMT caps, one connector block for the 12V power in, one grommet that secures the power cable to a side wall of the enclosure, one L78 SMD voltage regulator, and three THT protection components that are bulkier:

An 1.8 g TVS diode: 5KP15A
An 1.2 g reverse polarity protection diode: LN5404
A 2.25 g power resistor: AC05000002200JAC00


texts:
I have a couple questions about my DIY LED installation.

Both FUSE BLOCKS have 20 amp fuses inline each input to the main terminal which leads to the PSU, so 6 to 1, each having a fuse inline such that both live and return have fuses.
Also I have ran this in real-world testing with my DMM so my math is of real world experience, these are visual lights so not full white. Also I limit them to 200 out of 255 in programming.
The last picture denotes my area of concern: What happens to my math at these posts while configured like I have? Also my lights are powered on one side, so a parallel circuit (right?).
Now I have read a lot—I mean a lot— saying to power both sides, but the manufacturer even says you don't need power on both ends, so I choose that route for less soldering and wires.

My lovely Photoshop drawings, enjoy:

Specs:

Wire AWG INFO: Don't laugh! Grossly overestimated power consumption first round.

PSU to TERMINAL BLOCK = 10 solid // can handle anything my project throws at it, the same for below
TERMINAL BLOCK to BUS BLOCK = 12 stranded
BUS BLOCK to LED STRIPS = 12 stranded superflex (yes I know this is too much; I'm new here)
DATA is ran with= 22 awg throughout from IC

LEDs:

WS2812B
120 LEDs per strip
2 strips per aluminum extrusion
4 aluminum extrusion strips

Power:

PSU = 300 watts // project takes approx. 288 watts so 96 percent power comp, little over the 10% mark
TERMINAL BLOCKS = 50 amp capacity using 20 amp fuses on both LIVE and RETURN // safety net???
LEDs = power consumption per 120 LEDs (pixels) per strip = approx. 6.25 watts // not alot yus
5 volt system, DC
Consumption per strip in amps = 1.25 amps // at full brightness roughly it changes with colors
2 strips combined is approx. 12.5 watts // 2 LED strips in an extrusion power consumption

Now in my first picture supplied, not V2, my lights lit up efficiently and safely. I ran them for 24 hours and my wires never got hot. Yes I did overkill (way overkill) on purpose as my solder skills are above average, so no shorts.

Will my V2 work efficiently as the first one when I switch over with the "CONSOLIDATION" of wires with the added second BUS BLOCK, thus bringing the spare LEDs to a BUS BLOCK and freeing up other terminal posts? Now with this alteration, I have connected (2) sources to (1) terminal block that once had only (1) source.

My strips do not have a closed loop // the LIVE and RETURN are only fed at one end.

I'm basically confused about what I'm doing to my circuit. Will it perform properly? I am not interested in changing up my circuit completely, as I have made a bunch of custom wiring for it, but if I am completely lost, please let me know.

Once again, the final question is: Will my (V2) drawing work for my 4 LED fixtures (8 strips @ 120 LEDs) @ 300 available PSU watts?

My math shows I'm at 96 percent at (V1) drawings, but when I make this alteration to the wiring and having two sources on on post, what does that do to my math?

Thank you for reading this and please let me know any material you have vested interests in, as I am always willing to buy a book and learn.


texts:
This is my first time making SMPS for my application, so parden my silly mistakes and questions if any.

I stay in India where 230V ac rms @ 50Hz is available. I took 210V as min and 250V as max input. I need to get 5V@2A as output and using TNY266 as offline switcher for SMPS regulation. I referred following 2 links for making my first design:
http://www.mouser.com/pdfdocs/2-8.pdf

https://www.fairchildsemi.com/application-notes/AN/AN-4137.pdf

I calculated all the values which I attached in excel sheet.
https://1drv.ms/x/s!AhoWru2BCG9EgoRuFUzRit8UTTyGbg

It seems I need to wind transformer myself. So, I calculated primary and secondary turns used the table given in below link:
http://www.powerstream.com/Wire_Size.htm

So, primary is 144 turns of AWG 27 wire based on switching frequency and current and secondary is 4 turns of AWG 15 based on current but the switching frequency of that AWG is very low compared to the switching frequency of TNY266 i.e. 132 kHz. Did I select the correct AWG of wire for primary and secondary? And as per Infineon-Mouser design guide, I have decided to use EE16/8/5 core, is this the correct selection?

Am I doing correct calculations? If not, what are the corrections? Any recommended readings on subject to help design power supply and transformer design?

Thanks

Ashutosh


texts: Right kind of resistance wire for near-skin heater?

texts:
I'll be up-front and say I know jack squat about electrical engineering aside from "conductors heat up when you run current through them."

I'm looking in to building a low-voltage (~12-24 volts) personal heater that I can attach to the inside of a jacket; basically a small battery-powered electric blanket with no control system other than just unplugging the battery when it gets too hot and plugging it back in when it gets too cold. I'm not sure how possible this is to do safely though.

My main question is, what should I use for the heating coil? I was hoping to have a long wire that zig-zags over most of the back of the inside of the jacket. Kanthal wire is really cheap right now 'cos of all the people wanting to build vaporizers; is that an appropriate material? If so, what specific mixture and gauge should I be going for?

Looking at the specifics it seems like it's meant for extremely high temperatures, whereas I want something that stays around 30-40 degrees Celsius on low voltage. I can't seem to find anything that says it's designed for that kind of application, though. Am I barking up entirely the wrong tree?

Is this a practical idea at all?


texts: subtracting binary numbers using 2's complement

texts: Is it usually to not have  a carry in the two's complement method for subtracting two binary numbers when we subtract a large number from small one ?


texts: Arduino Circuit for High Power LED + Servos

texts:
I'm new to the Arduino game, but have experience with electronics in general. I am hoping to hook up two servo's and a high power (1W) LED up to an Arduino, to control them. Due to my inexperience, I thought it would be best to check on stack-exchange to see if this circuit will work.

My main uncertainties with this circuit are:

Is the LM317 Transistor the right component?
Is the 100Ω Resistor the right size for the 1W (3.3V, 0.33A) LED?

If someone is able to give some advice for this set up that would be amazing! I apologise in advance for the non-standard diagram. (Image attached)

EDIT:

Circuit Lab (UPDATED) circuit below

simulate this circuit – Schematic created using CircuitLab


texts: How could I efficiently implement this "TTL load"?

texts:
I'm attempting to test a parameter of an IC to the specifications listed in the data sheet.  The data sheet describes the following load circuitry for the output:

The data sheet notes that CL be 50pF minimum, and that the diodes be 1N3064 or equivalent.

The device I'm testing has six outputs that need to be tested for an implied total of 42 discretes that I'd need on my PCB.  I suppose I could use a header/jumper system to change which output of the IC is connected to a single load circuit on the board but that would require the load to be not that close to the output, sort of on it's own "branch" of the trace which I believe would be detrimental to the timing measurements I'm trying to make.

I suppose I have a few questions, any of which could help me here:

When the data sheet says "1N3064 or equivalent," what parameters of the 1N3064 are important?  The 1N3064 is an axial device and I will probably have to find a surface-mount equivalent.
Is there something magical about this configuration that I'm missing?  For example, that four diodes actually being equivalent to some other type of component that would be easier to place on a board?
Would switching a single load with jumpers make my life easier or more difficult?


texts: A simple on-circuit RS-232 to USB converter

texts:
I want to interface a PIC microcontroller (18f452) to a PC via the USB port. I learned that there is a USB class for serial communication so I will not have to write device drivers for it.

I want to know a simple way to connect my PIC to a USB port. I prefer a one IC circuit.
Is there an IC that will do my job?


texts: Is there an opensource equivalent to Phidgets?

texts:
For those who don't know, Phidgets are a hardware platform for interacting between PCs and hardware; they're a sort of "industrial lego".  They have DIO, relay drivers, sensors etc.  Their key utility though is thaty everything communicates either through USB or though their "hub" which is a USB device, and they have a very simple and uniform API that makes developing with them very quick and easy.  I use them a lot at work for small-scale industrial control and prototyping.

My problem with phidgets is that since they're closed source I only have access to their ecosystem meaning there is no way to add to it with my own parts that play well with their ecosystem.

Is there an open source software/hardware project out there that fills a similar niche?  Even if its less developed (I have no problems contributing my work towards the things I need to such a project).


texts: Shifting voltage level for reading sensor output on microprocessor

texts:
I realized a prototype-board with an old ATmega8 and a particle dust sensor. Both supplied with the 5V. The sensor output voltage is normally high (>4V), and falls below 0.7V if the sensor detect the presence of the dust. The percentage of dust depends on the time in which the output of the sensor is low in a 30sec interval.

Here the datasheet: http://www.seeedstudio.com/wiki/images/4/4c/Grove_-_Dust_sensor.pdf

Now I have to switch to the more modern ATXMega256A3BU, which can't receive a 4V level in input because is supplied with a 3V3.

What is the best way to interface these two devices? With an high-speed op-amp as comparator? With an <1 gain op-amp?


texts: How to convert exponential output to linear output

texts: I have a sensor which gives me roughly exponential output from 0 to 6 volts. How would I convert this to a linear range?


texts: What are the advantages of having two ground pours?

texts: I've seen many 2-layer PCBs that have a ground pour on both the top and bottom layers, I was wondering why do that ? and wouldn't it be better to use the top layer for power and signals and the bottom layer for ground to simplify the routing and also taking advantage of the capacitance between the planes ?


texts: Voltage drop in Analog inputs due to long traces length

texts: I am using ADS1278 chip. Analog inputs to this chip have been routed in differential pair manner. The differential pair inputs trace length is maximum 9 inch within the board from the ribbon connector to ADC chip. So .. Does this cause a voltage drop... My input voltage level is plus and minus 2.5V differential going to ADC.


texts: Battery size/type depending on desired usage

texts:
Directly below is the overview of a project that has been working well for around three months.

A 6 Watt, 12V LED spotlight powered by a 12V 7Ah sealed lead acid battery, controlled by a timer switch that runs the light for 10 hours a day. The battery is charged by a 12V 50 Watt solar panel with a solar charge controller between the panel and the battery.

The problem that started occurring a little after three months is that the battery will no longer run the light for the full 10 hours. When the battery was fresh from the store, I had timed how long the battery could run the light straight, and it was close to 13 and half hours. When I was doing the math for how much battery I needed to run the light for 10 hours, I did not take into consideration that lead acid batteries do not like being fully discharged on a daily basis. I believe I have ruled out the solar charging as a suspect by charging the battery on a battery charger with the same outcome.

Is there a particular type of battery that would be better suited for this type of usage or would my best option be to get a sealed lead acid battery that can handle 10 hours while only being discharged 50/60/70 percent?


texts:
I have a few questions about op amps, but I'm fairly new to the whole EE thing, so keep that in mind while answering. Thanks!

I am trying to use an op amp between a 6V solar panel and a 4.8v NiMh battery as a comparator. I want the solar panel to stop charging the battery when the battery voltage hits 5.6v. I'm using the comparator in a inverting circuit and I was wondering two things:

Is there a voltage drop from +Vcc to Vout?
If the panel outputs 200mA max, will the battery charge at the same current?

Also, I'm currently a ninth grader and I don't have any opportunities to learn about electronic engineering. I tried using the Internet as a tool for learning, but it hasn't gotten me very far. Is there any way that you would recommend going about learning the subject?

Diagram below

Thanks, Jack


texts:
Can there be a circuit or a device(probably a semiconductor) which allow flow of current only at a minimum threshold voltage?

I've heard about comparator but I am not able to understand how they work(their internal structure and circuitry).


texts: Zooming in closely in LTSpice moves the cursors

texts:
I'm sorry if this has already been answered, but I could not find anything related to this, even in LTSpice documentation.

Whenever I place a cursor on whatever point of an LTSpice plot, if I zoom in very closely into an area where the cursor is not already present, the cursor will get moved to the leftmost or rightmost border of the newly zoomed region. In other words, I would like the cursor to stay locked where I want it to be and where I put it in the first place, regardless of what region I am actually zooming into.

I hope I have explained myself clearly.
Thanks in advance for your help.


texts:
Why the power supply plugs of some modern electronic equipment have ground and some other ones -- with the same power, same manufacturer, same purpose -- don't?

For example: I bought 90 Toshiba Portege laptops, all of the same model, about 50 of them were delivered with grounded power supplies and some 40 with no ground.

I am aware of Why would we need to ground an AC source? but it does not address the question above.


texts: How to trade off connection styes in mixed gnd systems( power gnd and signal gnd)?

texts:
I am using a motor driver L6235 from ST:application note.On page 6, it gives me a layout suggestion:

it says that the SIGNAL GND and POWER GND should be connected in a single point: the negative part of C6. I think the reason is that signal and power part should have the same voltage reference and a single port has enough impedance to seperate noises from power GND. Is it reasonable?

And my question is that what if I have three L6235 in one system. They have the same logic supply and power supply.And if I have only one single point for POWER and SIGNAL GND, it will have following drawbacks:

and if I have multi-point connections it will have equal voltage reference, but the impedance between POWER GND and SIGNAL GND will be small. the noise may go to SIGNAL GND.

So, how do i make choices?


texts: Is there a chip capable (perhaps with a loop antenna) of sensing a 400-500 Gauss magnet at a distance of several inches?

texts:
Is anyone aware of a chip that is capable of detecting the approach (within several inches) of a fairly strong Neodymium magnet (~4000 Gauss):
https://www.digikey.com/product-detail/en/radial-magnet-inc/8193/469-1004-ND/555328
either as a perturbation of the ambient field or as a digital indicator if field strength exceeds a certain threshold?


texts:
I have two dell laptop Li-on batteries (J1KDN, 11.1 V Capacity 48Wh, Min 4.2a).
One battery seems to loose its charge very fast and the second one just turns turns off around 70% (with no warning).

Before disposing them I was thinking that I might be able to create one of them by combining the individual cells that are still good from both batteries.

Each battery consists of 6 cells and each cell has 3.6 V , I have tested one of the batteries from the two connector terminals and it gave me 11.4 V (higher than the 11.1 on the label).

So the question is how can I test each cell and verify which one is a keeper or not? and number two can I do that using only my multimeter or I also need additional equipment and what is it if any?

(The way that I was thinking of doing it was just checking for each cell if it is between 3.0-3.6 V but I am thinking that this is very simple to be the correct and only way).


texts:
I am trying to write a testbench for a 16-bit RISC processor using verilog in Xilinx.
I have the following modules:

- TOP
    -datapath
       -instruction_fetch
            -program_counter
            -instruction_memory
            -instruction_register
       -MUX21
       -alu
       -MUX41
       -general_purpose_reg
       -data_memory
    -control_unit

My question is : To get this to work do i need to create just one test bench for the 'TOP' module and have '$display' statements for each module inside it?

FOR EXAMPLE, if i have to display output of the alu module then should I have the display statement in the test bench for TOP?

module top_test;

    // Inputs
    reg clk;
    reg rst;
    reg start;

    // Outputs
    wire [4:0] PS;
    wire [3:0] opcode;
    wire [15:0] PC;
    wire [15:0] IM_instr;
    wire [15:0] IR_instr;
    wire [14:0] CV;
    wire [15:0] R1_reg;
    wire [15:0] R2_reg;
    wire [15:0] R3_reg;
    wire [15:0] R4_reg;
    wire [15:0] R5_reg;
    wire [15:0] R6_reg;
    wire [15:0] R7_reg;
    wire [15:0] R8_reg;
    wire Z;
    wire [15:0] A_ALU;
    wire [15:0] B_ALU;

    // Instantiate the Unit Under Test (UUT)
    TOP uut (
        .clk(clk),
        .rst(rst),
        .start(start),
        .PS(PS),
        .opcode(opcode),
        .PC(PC),
        .IM_instr(IM_instr),
        .IR_instr(IR_instr),
        .CV(CV),
        .R1_reg(R1_reg),
        .R2_reg(R2_reg),
        .R3_reg(R3_reg),
        .R4_reg(R4_reg),
        .R5_reg(R5_reg),
        .R6_reg(R6_reg),
        .R7_reg(R7_reg),
        .R8_reg(R8_reg),
        .Z(Z),
        .A_ALU(A_ALU),
        .B_ALU(B_ALU)
    );

    initial begin
        // Initialize Inputs
        clk = 0;
        rst = 0;
        start = 0;

        // Wait 100 ns for global reset to finish

    #100 ;
    rst = 1;

//  $display($time, " alumod A_in=%b,B_in=%b,ALU_out=%b", A_in, B_in, ALU_out);
    end

    always
       begin
          #5 clk = !clk;
         end

endmodule

alu module code :

module alumod(clk,rst,load_SR,ALU_opcode,A_in,B_in,ALU_out,data,carry,Z);

    input clk,rst;
    input [15:0] A_in,B_in;
   input [2:0]  ALU_opcode;
    input load_SR;

   output [16:0] ALU_out;
    output [15:0] data;
    output carry, Z;

   reg [16:0] ALU_out;
    reg Z;

    always@(ALU_opcode or A_in or B_in)

    case(ALU_opcode[2:0])

    3'b000:  ALU_out = A_in + B_in;
    3'b001:  ALU_out = A_in - B_in;
    3'b010:  ALU_out = {{16{A_in[15]}},A_in} >> B_in; //ARITHMETIC
    3'b011:  ALU_out = A_in << B_in;            //LOGICAL LEFT SHIFT
    3'b100:  ALU_out = A_in >> B_in;            //LOGICAL RIGHT SHIFT
    3'b101: if (A_in < B_in)                                    //SLT
                    ALU_out = 1;
               else
                    ALU_out = 0;
   3'b110:  ALU_out = ~A_in;                    //INV
    //'b111: HAMMING DISTANCE

    //default: alu_out = ;
    endcase

// Z REGISTER MODULE
always@(posedge clk or posedge rst)
        if(rst)
            Z <= 1'b0;
        else if(load_SR)
            Z <= (data == 0);
        else
            Z <= Z;

        assign data =  ALU_out[15:0];
        assign carry =  ALU_out[16];

endmodule


texts: Getting started with TinyFPGA board (Lattice Semiconductor MACHXO2 chip)

texts:
I'm a bit of a newbie with FPGAs.

Trying to run the project from the "Getting Started" section of the Lattice Diamond manual.

These are the source files:

count.v:

module count(c_up,c_down,clk,rst,c_up_2,c_down_2,c_down_3);

input clk,rst;
output [2:0]c_up;
output [2:0]c_down;
output [2:0]c_up_2;
output [2:0]c_down_2;
output [2:0]c_down_3;

count_up count_up_inst (.clk(clk), .rst(rst), .c_up(c_up));
count_down count_down_inst (.clk(clk), .rst(rst), .c_down(c_down));
count_up_2 count_up_2_inst (.clk(clk), .rst(rst), .c_up(c_up_2));
count_down_2 count_down_2_inst (.clk(clk), .rst(rst), .c_down(c_down_2));
count_down_3 count_down_3_inst (.clk(clk), .rst(rst), .c_down(c_down_3));

GSR GSR_INST( .GSR(rst));

endmodule

count_down.v:

module count_down (clk,rst,c_down)/* synthesis GSR="DISABLED" */;
input clk, rst;
output [2:0]c_down;

reg [2:0]c_down;

always @(posedge clk or posedge rst)
     begin
        if (rst)
           c_down = 3'b111;
          else
           c_down = c_down - 1;
      end
endmodule

count_up.v:

module count_up (clk,rst,c_up)/* synthesis GSR="ENABLED" */;

(the rest is essentially the same, just on reset init to 000,
and on clk's posedge increase instead of decrease)

There's also count_down_2.v and count_up_2.v that do the same, increasing or decreasing in steps of 2.  And there is a count_down_3.vhd that seems to do the same, just in steps of 3 when counting down.

The synthesis goes well all the way to generation of the JDEC file. I'm using the TinyFPGA programmer software, and that one reports erasing, flashing, and verifying all OK.

However, the pins of the TinyFPGA board don't move at all. The red LED is on (if I'm understanding correctly, that's just an indicator that the board has the 3.3V power in). Pins 12, 13, 14, 15 show a 1011 output, and most other pins are at 0.

Aside from the obvious question of why is it not working, I have a couple of concrete questions:

How do I specify the mapping of the pins? (i.e., output signals/variables in the Verilog code corresponding to specific pins on the chip)  I can't seem to find any such definition anywhere in the project.  I know I specified the correct chip (LCMXO2-1200HC-4SG32C); even if the application just knows the mapping, how do I know the names I need to use to output to or input from a given pin in the chip?
Do I need to set up the clock? (I guess maybe the chip internally generates a clock with default characteristics --- but I'm not sure whether that's the case, and whether that's what I'm missing?)

Thanks!


texts: If I generate code using STM32CubeMX then which files are related to CMSIS and which files are related to HAL? My toolchain is Atollic TrueSTUDIO.


texts: Unknown logo on FGS25N120ANTD IGBTs. Which semiconductor manufacturer is this?

texts:
I bought 5 FGS25N120ANTD IGBTs from my local vendor a while back.

I was unable to identify the manufacturer, based on the logo.

Can somebody help me out?


texts: What is wrong with this DC-DC smps desgin

texts:
The PWM signal is from microcontroller (STM32F051***) about 500KHz (48MHz/96)=500KHz . note : control register for PWM - CCR : 0-65000

When I connect battery and PWM signal : CCR = 1, i get output about 1.4v. but changing duty cycle little bit more (CCR = 2) , i get drop in voltage : 0.87v. WHY? for CCR = 3 , no output 0 .

CAN anyone explain why I get that behavior?
I don't have oscilloscope nor henerymeter.


texts:
I have a circuit like this that has a 12vDC power supply.  I would like to measure the voltage on either side of each of the lights with the arduino's analog input pins, but the arduino's max voltage is 5v.

How would I keep the voltage at least proportional to its value while making it less than 5v?

Normally to read voltage from the arduino, I would get the value, which is a number in between 0 and 1023, then multiply it by 5/1023 to give me a voltage between 0 and 5 volts.  Could I just stick a resistor between the point on the circuit and the arduino, then multiply the value from the input by 12/1023?


texts: How to short motor terminals using Sabretooth 2x32?

texts:
I am using a Sabretooth 2x32 motor driver and an Arduino Uno for control via serial.

I am unable to brake the motor using the Sabretooth whereas if I manually short the motor terminals by hand, they are locked. I have disabled freewheeling on the Sabretooth.

Does anyone have any idea what setting is required to brake motors using Sabretooth?

For reference, I have these motor drivers. Product Spec.


texts: Why does my lamp only work when plugged the "right" way?

texts:
I have found a halogen lamp that only works when plugged to the wall socket the right way. I am baffled by this behaviour.

The lamp is similar to this model, and uses a bulb similar to this model. The bulb is probably not important but the lamp may be if some internal electronics are the cause of this behaviour.

The plug is a Type C plug, no earth connection, just two symmetrical metal rods. The socket is European: AC, 220-240V, 50Hz.

As far as I can understand, it should not matter which way the plug is inserted into the socket.

If the lamp uses AC, then both rods will be alternating polarisation and both orientations should work exactly the same.
If the lamp works on DC, it will have some internal rectifier / regulator electronics inside that will transform the AC in DC. These circuits, by design, should work regardless of the orientation of the plug.

What am I missing? Which electronic design may result in a lamp only working if it is plugged in the right orientation and what would be the rationale to add such circuitry to the lamp in the first place?

Extra information:

Other appliances (such as laptop chargers) seem to work as one would expect in that socket.
The lamp exhibits the same behaviour in other sockets.


texts: How to construct this simple circuit properly?

texts:
I am a total newbie in electronics and circuit design. I am working on a project that involves a AC motor and four 1W LEDs. I found a motor that works for me and it comes with a AC/AC power adaptor (Adaptor's Output: AC 6V 500mA). I need to add 4 1W LEDs to the circuit that share the same power source.

After doing some research on the web I know I need to use a bridge rectifier to convert the AC to DC so the LEDs will work, but I don't know which rectifier to use. Also, I don't know which capacitor to use (to smooth the output) and if any resistor(s) need to be in the circuit. I included a schematic of the circuit, but I am not sure if the schematic is correct or not. Any help will be much appreciated.


texts: AVR ISP not working, strange signal level

texts:
I can't read the chip ID of the ATMega16m1 MCU using a AVRISP mkII programmer.

The ISP pins are connected directly to the MCU, the reset line has a 10k pullup to Vcc (3.3V).

When measuring the ISP lines using a oscilloscope (see below), I saw that the the MISO line is stuck at ~1.68V which isn't right I believe. When I connect the programmer to a Arduino nano clone it works properly.

Does anyone have a clue what might be wrong?


texts:
I was going through datasheet of mosfet gate driver. I wonder why is the value of component the specified one only. On page no. 13 fig 23, why the value of resistor between pin 3 and pin 6 is 10k ohm only and not any other value? Similarly, capacitors between pin 6 and 8 are of value 330pF. Why not any other value?
The attached diagram is of recommended application circuit provided by Avago Technologies. Also if I am to use it in LTspice with a mosfet, what are the additional components and connection that are to be made so that the driver can driver the mosfet? The mosfet is to be operated at a frequency of 100kHZ.


texts: Spice Transimpedance amplifier AC analysis

texts:
I'm trying to analyse the AC response of a transimpedance amplifier with LTSpice. I have a current source set to "small signal analysis" with 1mV as the input of the amplifier stage. I run and probe the output but I get 0dB at low frequencies. So I conclude that LTSpice is using the input voltage as reference and not the input current.

I believe I need to explicitly tell LTSpice to plot amplitude and phase of outputVoltage/inputCurrent signals. How can this be done?

If you need more information, please let me know.

Here's a picture of my circuit and resulting analysis. With a resistor of R1=1k I'd expect to get an amplitude of 20log(210mV/210uA) = 60dB at low frequencies. Instead I get 0dB.


texts:
I have a 6-layer board where the internal 4 planes are +15,GND,VCC,-15.  I was wondering if there was any advantage to doing a copper pour on the top and bottom layers?  I would probably leave them floating as I don't want to use micro-vias to say tie it to GND?

Is this actually a bad idea?  I.e. floating copper=antenna.

Would it be just as acceptable to have 4 layer board with the top layer having copper pour to VCC and the bottom having a pour to GND and keep the two internals as +-15?

Note that this is for a fairly low speed circuit which has some analog and digital parts.


texts: How to obtain a little 120 VDC from 240 VAC?

texts:
Is there some simple technique to efficiently produce 120 VDC from a mains 240 VAC supply?  All I need is < 50 mA.  Can something be done with just rectification and capacitors for example?  Large dropper resistor?  I want to run a few neon bulbs in DC mode.

EDIT:-

I only actually need one neon to run, but can have others if it makes the cicuit simpler vis a vis total voltage drop. I think a single neon bulb draws only about 1mA.

EDIT2:-

Appologies all, but thanks for feedback.  I think that this question is very badly put.  It's not the power supply per se that I want, but the neon bulb to run at DC current.  Should I ask another, better question?


texts: Programming an attiny85 and powering a circuit over a single USB-C port

texts:
I'm currently working on a RGB enabled controller stand that will include a circuit that does do two things:
-charge the controllers
-control rgb strips on the mount
I'm pretty new to electronics, and I never designed a circuit before, so I was hoping you would be able to  tell me if i did anything wrong in this circuit...
so here's the circuit that I made:

The circuit includes an attiny chip that will be programmable via the USB-C input, which will also provide power (5v3a. 5.1k pull downs for USB-C power omitted here as the breakout board comes with them pre-installed). It also has components for the rgb strip, including a switch that will toggle the lightning effect.
I'm hoping this circuit will allow me both to power everything over USB-C as well as reprogram the attiny if i want to, would it actually work?
Many thanks.
edit: I fixed some basic mistakes with the circuit.


texts: Powering the blue pill board from laptop and using another power supply at the same time, will this cause problems?

texts:
The components: a laptop, a blue pill board, a +5V power supply(taken from old PC).
I have a blue pill board(stm32f103c8t6 mcu). Schematic here.
I connect my laptop to the blue pill board via SWD interface(CN4 on the schematic) using an ST-LINK v2 debugger. So the board gets its power from the 3.3V coming out of the ST-LINK. I set PA0 to output a PWM signal.  Now, I will connect it to the servo motor. Making the following connections:
SERVO side   - blue pill side
signal cable  -         PA0
GND        -        GND
Connections are done, then I also connect GNDs of the 5V power supply and the blue pill board. So I made all grounds common.
Finally, I will connect +5V output of the power supply to the +5V input of the servo. This is the connection I suspect might be problematic. I don't know whether using these two power supplies(one through laptop and the +5V power supply) to power different parts of the circuit will cause problems(short circuits, harming the laptop or mcu, etc.) or not. Any explanation would be nice.
p.s: I am not able to draw a schematic now, sorry for it.


texts: Why do zeros in the right half of the \$s\$ plane reduce stability (i.e., gain / phase margin)?


texts: How do I create a permanent application from something prototyped with Arduino?

texts:
Part one of a three part series on transitioning from Arduino to a plain AVR microcontroller and minimum supporting components (part two, part three)

I've built up a project on my Arduino Uno to control various aspects of my beer brewing system. At this point it seems to be doing what I want, but I would like to reuse my Uno for another project. How should I move my project from the Uno and breadboard to a PCB, perfboard, or whatever? Any good solutions out there?


texts: Totem pole opto-isolator TLP152 won't work as intended

texts:
I've been working on this very confusing problem regarding making a TLP152 opto-isolator to work as intended. Here is my circuit using a TLP152 to work as a IGBT gate driver. TLP152 circuit diagram

No matter which way I try, i can't just have any signal at TLP152 output (pin 5). Ways I have tried: using signals ranging from 100 Hz to 50 kHz at 5V peak voltage, leave the LED of TLP152 on (no pwm signal), change TLP152's LED input resistor from 330 Ohm to 220 Ohm. Do you guys have any suggestion on how to make this thing work.

P.S: I have made a similiar circuit using TLP250 and it works, while using TLP152 won't.


texts: Novice question about high and low speed motors

texts: Why some low speed electrical drives employ a high-speed motor and some form of mechanical speed reduction rather than direct drive motor. Is it because of size?


texts: Measuring impedance frequency response on Low Power Board

texts: I have a low power board (2.1V DC). It runs a micro, some sensors, etc. I am interested in plotting out the impedance frequency response of the overall board so I can tell where the impedance dips. This will let me know any problem areas in my bulk capacitors or layout. I am curious how to go about this, and yes I know I can do a simulation, but would like real data.


texts: Stream Audio and WebCam Video through Radio Frequency

texts:
I and my friend would love to make a better communication system between us since his internet connection is not the best and neither is mine. We are 20 km away from each other.

Our project is to place a webcam in each other bedroom and microphone and stream it through radio frequency, then getting the signal on each other computers without the needing of internet connection, maybe just not on the computer but also on the TV, like if our bedrooms were somehow connected.

I'm new to this field, Radio Frequency, and electronics in general. I'm good at programming in various code languages but I've done only a few projects with Arduino.

I'm very fast at learning so if you tell me what to do, what components to buy, and what to study I'd like to start working!


texts: Wired AND Wireless Embedded Ethernet Project

texts:
Hey guys,
I would like to design a device that is capable of connecting to a PC via WiFi or a wired connection (ideally Ethernet as well). I would like for it to be possible for a wired connection to be used while a wireless connection to a remote device is also able to communicate with the device (using the WiFi). So for this to be possible i believe that I would need a WiFi module and a wired Ethernet adapter controller. I would prefer to use Microchip devices and I have been studying their line of Ethernet controllers but it seems like it would be quite a challenge to configure their firmware stack to work with a wired connection and a wireless connection at the same time.

I guess my other alternative would be to use WiFi and RS-232 so that way I only need the stack for the wireless connection. That would simplify things greatly but I lose my ability to have true remote control from outside the building on my wired connection.

I guess this project would be similar to a printer that can be connected to using either WiFi, or a wired connection, or possibly both at the same time.

Has anyone worked on a project like this or have any suggestions for me?


texts:
So I'm still new to electronics, and I've been taking a look at Boost Converters and such (just learning power supplies and the different types)...which got into explaining inductors. Needless to say it was a little bit to take in. Inductors seem quite complex for such a simple component.

Just so I have this straight, inductors resist change in current, so if the current is lowering it will "create" a higher voltage to try and make up for this according to Lenz's law. (Is this correct? ....does anyone know how this happens?).   When it is creating this voltage is the current being lowered or just drained quicker?
In a schematic such as this:

Lets pretend the diode wasn't there. What would happen? Would the inductor just keep building up energy with nowhere to go? Would it just dissipate in the air? In the Wiki article it said it would arc over to the next wire. Is there a limit to how far it can arc (like What if the wires were FAR away: would the inductor melt, or would the energy just dissipate in the air?
What determines how much energy an inductor can store? The number of turns? Or does the size of the inductor actually matter as far as "rate" of storage.
Unrelated Sort-of, but are there any "cool" experiments I can do with them to just kinda see how they work? I saw this one on youtube essentially he just has a switch that he turns on and off and you can see the voltage jump up super high. Im assuming this is how a boost converter works.

Sorry for the multiple questions, just trying to grasp the magic of inductors. They seem so simple (A coil of wire) but do so many crazy things.


texts: How to create .vcd file for power analysis through xpower(xilinx 10.1) software?

texts:
I had a verilog code. I did xpower analysis without .vcd file, with .vcd file(using simulate post route & route model)  and .vcd file (using $dumpfile("test.vcd") ). I am getting different result in all cases. I am explaining it below:

1)xpower analysis without .vcd file
Result are:

total power = 0.30292 W

2) xpower result with .vcd file(using simulate post route & route model)

total power=0.30361 W

3) Xpower result with .vcd file :
I used below lines with testbench to generate .vcd file:

initial begin
   $dumpfile("test.vcd");
   $dumpvars;
   #1000 $dumpoff;
end

Result:

    total power = 0.30184 W

Why all result in different total power? Should i need to do any correction?

Thank You


texts:
Note: I have added a schematic since originally posting. Also here is the data sheet for the chip and here is a link to an overview of the actual board that I am using.

I am working on a project that uses an adafruit pro trinket 5v/16mhz to control a TMC2208 silent step stick in order to drive a small nema23 gear motor with a relatively light load. I know that the stepper driver is a bit underrated for a nema 23 but in this application, it should be fine.

I have used setups like this before with no problems but I am finding that if the 24vdc that I am using to drive the stepper is connected to the VM/GND pins, the driver burns up immediately. This is with/without the the 5v logic power connected and with/without the stepper connected. I have burned through a number of these and I seem to have some sort of fundamental lack of understanding of some aspect of this setup although I have used setups like this without issue. In this case, I used a few different 24v power supplies which were all rated at 5amps, do I need to use a lower amp power supply? I have check the polarity and I have also checked to make sure that I am not sending 24v to the logic pins, just the motor power pins.

Basically, under what circumstances can I connect voltage to the motor power pins of these stepper drivers without causing them to burn up. I can't get any more TMC2208 locally so I will use something like the DRV8825 but I'm having the same problem. I feel like I am going crazy and I need to finish this project for tomorrow, any help would be appreciated.
Thanks

simulate this circuit – Schematic created using CircuitLab


texts: Controlling a Servo with a TLC5940 (calculating PWM setting)

texts:
I'm trying to control a few servos and a bunch of RGB-LED from an arduino board. To do that I'm going to chain together a few TLC5940 chips. The issue I'm trying to resolve at the moment is what PWM settings do I need for the servos; particularly what are the min rotation and max rotation settings?

My servo is a: HiTech HS-55. This site: http://www.servocity.com/html/hs-55_sub-micro.html says the servo runs on "+Pulse Width Control 1500usec Neutral" with a 600us pulse being -90 and a 2400us pulse being +90.

To figure out how to generate pulses that long with my PWM driver I need to know the frequency the driver runs on. The data sheet for the driver: http://www.ti.com/lit/ds/symlink/tlc5940.pdf says this about the PWM operation on the bottom of page 19:

  The grayscale PWM cycle starts with the falling edge of BLANK. The first GSCLK pulse after BLANK goes low increases the grayscale counter by one and switches on all OUTn with grayscale value not zero. Each following rising edge of GSCLK increases the grayscale counter by one. The TLC5940 compares the grayscale value of each output OUTn with the grayscale counter value. All OUTn with grayscale values equal to the counter values are switched off. A BLANK=H signal after 4096 GSCLK pulses resets the grayscale counter to zero and completes the grayscale PWM cycle (see Figure 21). When the counter reaches a count of FFFh, the counter stops counting and all outputs turn off. Pulling BLANK high before the counter reaches FFFh immediately resets the counter to zero.

Unfortunately I don't have any idea what that means. (I think) I know that the PWM driver gets some form of clock signal from arduino but unfortunately doesn't help me figure it out.

Can anybody help me figure out what settings I need to use on the PWM driver to generate the desired pulses. The closest value will work. For my application if the servo gets within a couple degrees it should be close enough. Will this even work at all? My understanding of how servo's work is that they generally need a pulse every 20ms so even if I calculate how to generate the correct pulse duration I doubt it will magically work out to a pulse every 20ms. Will the servo accept the input?


texts:
I am using an Arduino Nano that has output pins of 5 volts. I want to use the Arduino nano S pin to open and close a MOSFET for powering on and off a Benewake TFmini Plus distance sensor ( http://en.benewake.com/product/detail/5c345cd0e5b3a844c472329b.html ). The TFmini Plus sensor has a power consumption of 85mW~550mW and runs on 5V. What MOSFET should I use as a switch to connect the 5 volts on and off for powering the TFmini Plus and have the switch controlled by the signal pin from the Arduino Nano?
I am new to this and any information on understanding how to learn what MOSFET to use is extremely helpful. MOSFETs are new to me. Thank you for any advice you can offer.


texts: How is the 220V line in US different from other parts of world? Does a US 220V line need two switches for each wire?

texts:
Today my A/C compressor had given up its ghost and when I tried to disconnect it from the wall switch after turning OFF the wall circuit-breaker,I assumed like most 110V lines where only one line (Live-L) lights with neon tester.

When the circuit breaker was turned OFF the neon tester on A/C switch line turned OFF and I assumed the power was out. But while disconnecting I accidentally touched the other wire and I received a shock. On testing with neon tester I noticed the light was glowing for the other line also and I later discovered it had in fact two breakers(no handle tie) for the A/C circuit. When I checked on my normal 110V lines the neon test light glows only on one wire i.e., Live wire.

Even most of my google searches showed a 220V line with just L and N. So,doesn't the US 220V have a neutral?


texts:
I am designing a 4- layer PCB with  Ethernet (RMI) and integrated magnetics, which I want to make as good as possible with respect to signal integrity and EMC.
RMI, so the frequency is 50 mHz.
Because of practical reasons I have a length mismatch between the Tx+- and Rx+- diff pairs of about 4 inch. (Note : only a mismatch between the pairs but not within one pair)

I found a lot of information online and on this website about length matching between Tx + and Tx - or Rx+ and Rx-, but not about the length mismatch between the two pairs (intra pair if I am correct).

Question : What effects does this mismatch have? Do I need to care about it with only 4 inches ?
If not, in which situation would I need to take into account ? and how?


texts: Quartus II: USB Blaster not found, even after installing the driver

texts:
I've purchased this USB blaster: https://www.amazon.com/dp/B07F5H5LPZ/

Because I have this Ep2c5/ep2c8 dev board, I've been following this video to begin my work with FPGAs: https://www.youtube.com/watch?v=le6Jo5DpLao

Here is my problem. After connecting the USB Blaster to my Win7 computer for the first time and installing the driver from altera\11.1sp2\quartus\drivers, the USB Blaster shows up in the control panel as "USB-Blaster(Altera)" but Quartus II doesn't show it in the Programmer's Hardware Setup page.

In troubleshooting, I also tried installing the same version of Quartus II and the USB blaster on my Win10 laptop, but the driver isn't signed for win10 so I dropped that approach. Back on the Win7 computer I tried using the command prompt to open altera\11.2sp2\quartus\bin\jtagconfig.exe and saw it read out the message "No JTAG hardware available".

Is there something obvious that I'm doing wrong here? Do I have a bunk USB Blaster? Do I have the wrong hardware or software altogether?


texts:
I am trying to extract analog sample data from an xbee packet that are present in the 20th and th 21st bytes. However after extracting them into the serial monitor the garbage value that is received turns out to be wrong.

Here is the output I receive in the serial monitor :

First column- lsb
Second column -  msb
The code for extracting data looks like this:

if(Serial.available()>21){

if(Serial.read==0x7e){

for(int i=1;i<19;i++){

byte discard=Serial.read();
}

int analogMSB=Serial.read();

int analogLSB=Serial.read();

int analogReading=analogLSB+(analogMSB*256);

When I calculate lsb + msb*256 for the above , I receive negative values as well which is undesirable. Please tell me how I can rectify this issue .


texts: Is my measurement setup correct for the common mode frequency response?

texts:
I’m using a USB scope which can be used as also a network analyzer. For a network like a passive filter, to obtain Bode plots one input channel is set for reference the other as output. And the input signal is set and swept by a wave generator input. Settings are done via a software. The input channels are differential; for example for channel one Ch1+ and Ch1- are the inputs for a signal.

Below is the wiring for an RC low pass filter to use as a network analyzer and to obtain Bode plots:

W1 is the sweeping wave generator input; Ch1 is the reference channel; Ch2 is the output; Ground is the common ground for input channels and W1.

Now I want to obtain the common-mode response Bode plot of the following choke circuit by the same device:

Is my way of wiring correct below?:

Will I obtain common mode freq. response if I use the above measurement setup?

Second attempt:


texts: How to measure capacitor maximum voltage rating

texts: I have a lot of mixed SMD capacitor where i have no idea what is the voltage rating and is a waste. Is there any method to determine voltage rating of a capacitor? i tried connect resistor and capacitor in parallel and measure the transient using oscilloscope, is there any calculation required from the waveform?


texts: How to synchronize two different precision measurement instruments?

texts:
I am trying to design a turbidity detector and this has to be sensitive to tiniest amounts of contamination present in a sample fluid. My setup consists of a 780nm laser whose current I control with an SMU. Light from this laser passes through a cuvette which contains the fluid and the intensity of the transmitted light is detected by a photodetector using an electrometer. The laser has an in-built photodiode and I use that to monitor any change in the laser's intensity, using another electrometer built by a different manufacturer. My intent here is to normalize the transmitted intensity by the laser's input intensity, to factor out laser's intensity variation. However, the laser is pretty shabby(intensity varies a lot) and therefore I need the two instruments to be precisely time-synced when they make a measurement. What's the best way to achieve this?

What I have thought of:

Send "trigger" signal to both the devices when I want to make a measurement. The problem here is that the electrometers are manufactured by two different manufacturers and there might be a delay-to-measurement difference between the two.


texts: How can I add high and low voltage signals to a high voltage DC offset?

texts:
It's only a theorethical question, since I'm not really going to build this circuit... I'm just curious, that's all.
Anyway, thats my question!

I have these signals:

3 kHz, 1V (peak)

20 Hz, 100V (peak)

(DC offset is 70 V)

Since I doubt it would be impossible to add them (only impractical, I guess), I was wondering:
how can I create a single signal out of those parameters?... Or better:
Is there a "standard" method do such things when op-amps cannot be used?

EDIT:
Thanks for your answers: each one is a different approach to solve the problem, so thank you, really!


texts: What does it mean for a signal to be 5V with respect to one leg of an AC input?

texts: This power supply provides 5V with respect to one leg of the 24 VAC input.  I'm trying to understand what that means because this provides 1.2 amps and I only need 20 mA for what I'm trying to do.  It seems like hot and neutral are going to each end of the regulator.  Does this mean a high signal would be in phase and amplitude with 24 VAC and a low signal would be the 24 VAC peak minus 5V?  Can I do something similar to this with a LM7805?


texts: Ultra low leakage capacitor for nano amp current source

texts:
I am looking for capacitor type which has very low leakage such as 0.5nA since I am working with a sensor which generates between 0.9nA to 0.55uA.

Based on my research Film or foil Capacitor has the lowest leakage but not even close what I looking for, they all close to micro and not nano.

Note:  the cable lenght is 20ft not 200 sorry


texts: What is the fastest way to drain all the charges of battery?

texts:
I need to build battery draining circuit which must finish off battery's charges as fast as possible. I've designed one, but not sure is it optimal one or not? I decided to connect single R to battery as shown in circuit.
And Since the maximum power which battery can take is

  Pmax=r*(I)^2

and

  R=(V-r*I)/I

, our minimum R must be

  R=(V/(Pmax/r)^0.5)-r

. I thought too much power on battery may cause disaster, output maximum output current must be limited to

  I=(Pmax/r)^0.5

Can this be optimal solution? And I'm not sure if equation for power which battery takes is true or not.

simulate this circuit – Schematic created using CircuitLab


texts: Cat5 cable for low voltage underwater application

texts: I am setting up a design for a small submersible ROV and planning to try cat5 cable to power the various components. I have found the ratings for the cable, however I have a question about water vs heat dissipation. Apparently, I can get approx .5-.7 amps of power transmission safely for the motors, but would I be able to push it a little more to 1amp if the cable is submerged in cold northern lake water? The cable would be 100ft and I have factored in voltage drop due to resistance. Thanks for any advice.


texts: how to drive two pairs of DC motors with arduino

texts:
I want to power four independent DC motors of a rover with arduino. Besides the voltage (6.0V) I don't have any other information about the motors.

I decided to make the rover change direction like a tank, meaning that each side's motors (right side and left side) have the same speed, but right side has different speed than left side. I also intent to use one or two L293B or simmilar chips.

I have thought of several ways of creating the circuit:

Case A: Four PWM pins of arduino, each one for controlling an induvidual motor. This means that two L293B chips are required:

PWM_front_left and PWM_front_right connected to the first L293B
PWM_back_left and PWM_back_right connected to the second L293B

Case B: Two PWM pins of arduino, each one splitting

PWM_left splits to PWM_front_left and PWM_back_left
PWM_right splits to PWM_front_right and PWM_back_right

Each one controls an induvidual motor. This means that two L293B chips are required.

Case C: Two PWM pins of arduino, each one connected to left channel and right channel of just one L293B. Two motors will be linked to the left channel and two motors will be linked to the right channel.

Are there any advantages or dissadvantages for each one of these cases?

Also, I would like to ask something about the logic pins. For each channel except of the PWM, two logic pins are required:

Pin_A (1) and Pin_B (0) for clockwise
Pin_A (0) and Pin_B (1) for anticlockwise

Since everytime B = NOT(A), instead of using two logic pins, I want to use one logic pin splitting in two parts. The first part is connected directly to the L293B. The second part passes through a hex inverter, exits as an NOT(A) and is been connected to the L293B. Is that possible to work?


texts: Combining two led strips with separate controllers

texts: Out of practice and have forgotten basic principles but would like to combine two led strips to one controller so they operate in sync. Have combined output from sensor into control box but outputs from control boxes not in sync when using RGB light shows. How can I split output from one controller to two light strips using driver and controller in image. Thanks


texts: What's The fundamental difference between interrupts and delay in embedded programming?

texts:
I'm new in embedded programming in C, just getting to understand coding.
Is there a fundamental difference between an interrupt function and a delay function?

I would greatly appreciate answers with example code.


texts: Driving IR LEDs using PWM - measuring current & current source questions

texts:
For a project I'm currently working on, we're trying to drive 940nm IR LEDs (Kingbright L-934-F3C) using PWM, regulated by an Arduino Uno. We've run into several issues during our prototyping process and could use some help!

We want to illuminate a 50 x 70 cm area from above using these LEDs, to be able to take a photo with an IR-sensitive camera when it's dark. There will be several objects located on this area that need to be lighted. We'd like to use as few LEDs as possible, so our reasoning is to pulse these LEDs at their maximum current while the camera is taking the picture, to achieve maximum illumination.

The Kingbright datasheet specifies an peak forward current of 1.2A, when a duty cycle of 1% and pulse width of 10μs are used. However, it doesn't say at what voltage (the forward current vs forward voltage graph doesn't extend that far). This peak current value doesn't seem to jive with the max. specified voltage of 1.6V (according to the graph, this happens at 50 mA).

  (1) Are LEDs able to take massive amounts of voltage when pulsed at
  such short times, as long as the peak current stays below the limit?

We currently use a Velleman current & voltage source 30V/3A(http://www.velleman.eu/products/view/?id=420136). We hooked it up to one IR LED using the PWM settings as described in the datasheet and set the current source to 1.2A. The LED instantly blew up as the voltage rose to 30V. When used as a voltage source, further experimenting found that above 15V, the LED did not get appreciably brighter. At 15V, the single LED only appears to draw 40 mA (according to the display on the source).

  (2) As these voltage and current figures do not match the datasheet of
  the LED, perhaps the lab source doesn't display the correct current
  flow. How can we accurately measure this?

  (3) What's the longevity of the LED when you operate it at the limit?
  Does it have enough time in between pulses to dissipate the heat that
  is generated when running at 1%?

We found that a single LED gave a fairly disappointing amount of light. We're thinking of hooking up around 15 parallel strings of 2 LEDs connected in series. If we were to put 30V into the array (2*15V), assuming that the LEDs can draw a peak forward current of 1.2A, the array would draw a current of 18A.

  (4) Is it possible to get a peak current of 18A @ 1% duty cycle out of
  a 3A source without blowing it up?

Lastly, we're very interested to see other peoples' solutions for this kind of build. I have the feeling that PWM is mostly used to 'dim' LEDs instead of being able to overdrive them to the max, but I might be mistaken. We'd love to hear your opinion on this!

Edit June 25th

Thanks for the responses! I will try to give some background information. As you might have guessed, we're not really electronics ninjas, but that's exactly why we're asking!

The lab source is a Velleman LABPS3003SM (it's strange that the link isn't working for you, WhatRoughBeast, it works over here!)

Responding to the question of CL.: we're trying to pulse the LEDs at the 1% duty cycle for the duration of a single snapshot of the camera, at 3fps. We're homing in on the actual moment that the photo is taken but this is proving difficult. In the final product, it would be great if we would be able to only pulse the LEDs exactly when the picture is taken.

Responding to the questions of mkeith: unfortunately, we do not have an oscilloscope. I'm don't have access to our prototype right now, but the PWM circuit consists of an IRF540N, with the gate hooked up to the Arduino (5V) and the source directly attached to the negative lead of the LED, no resistors.

The source was set as a voltage source, no current limit. This appeared to work when just a single LED was hooked up at 15V. When we tried to hook up 2 LEDs in series (and the voltage source set to 30V), the first of the LEDs in the series blew up.


texts: How does the circuitry work in the Symet robot?

texts:
I ordered this Symet robot kit and it only includes instructions on how to build the thing instead of actually teaching you exactly why and how it works. I even ordered this book that walks you through how to create it again but again does not teach anything about how the circuitry works. So stinkin' lame!

The circuit diagram on the top is how the book teaches you to build it and the diagram below is how the kit teaches you to build it.

The top one uses two different transistors and a FLED while the bottom uses 3 different transistors, an additional tiny capacitor and a diode.

The "robot" works very simply, storing some power in the larger capacitors then releasing it to the robot, turning the motor in bursts. My question is, how is this circuitry working? How are the two (and three) transistors working to make this happen? Also, what are the big differences between the two and why is one better than the other? Any and all details of how this is precisely working would help me tremendously!


texts:
Above is a TTL totem pole output NAND gate. There is a 120 ohm pull up resistor there. Since it is called pull up, can we say that the HI output will be connected to a very high input impedance? If so what can it be as an example? Aren't NAND gates in an IC are connected to each other by being ones output is other's input? I mean in the figure the output will be the input of another gate right? If so HIGH will not be 5V since there will not be input impedance unless it is not connected to a very high resistance.

Where is this NAND gate's input coming from and where is the output going to? If the output is 5V isnt it high for a new TTL gate input and if is not 5V why do we call the resistor pull up in there?


texts: Can I program a 3.3V ATmega MCU with 5V programmer (USBasp)?

texts:
short question:

I have ATMega8A at 3.3V
I have USBasp programmer at 5V (from USB port)
Can I program this AVR with this programmer directly?

Well, ATMega can stand 5V but it's powered with 3.3V so I don't know whether it will survive.

I don't want any level shifters: I don't have one and don't have space for that and it should be simple.

If I cannot connect that directly, then can I use a voltage divider (2 resistors) to divide 5V to 3.3? There's no need to do it from 3.3 to 5V because 3.3 is already high level for 5V...


texts: using an op amp in a battery powered circuit

texts:
I'd like to use a simple non-inverting amp circuit in a small project I am working on. The project is battery powered, so naturally the only voltage I have access to is 3.3v. My question is: how should I get the voltage for the -ve rail? Of course I can add a DC-DC converter but I'm sure this is already a solved problem so I figured I'd ask first.

Thanks!


texts: How to trim up voltage on DC-DC converter

texts:
I'm using the TVN5-2421WI DC-DC converter where I need an output of at least +/-6V (which will then go into 2 LDOs that will drop it to +/-5V), so I'm trying to use the trim pin for this, however the datasheet doesn't specify what value resistor to use:

Datasheet: http://docs-asia.electrocomponents.com/webdocs/1341/0900766b81341219.pdf

How do you figure this out? I'm very hesitant to use a potentiometer.

EDIT:
I found a datasheet for another DC-DC converter from Traco, and they have a formula for determining the trim output:

Datasheet: http://www.tracopower.com/products/ten25wi.pdf
What's the likelihood I can use this same formula?


texts: Can I safely replace rechargable NiMH batteries with consumer-grade ones?

texts:
I have a cordless handheld vacuum cleaner (Electrolux Rapid ZB4103) which is powered by 3 rechargeable AA NiMH batteries (1.2V 1300mAh) connected in series and stacked (glued?) in a pyramid to fit within the case. The batteries are typically recharged by placing the vacuum unit on a changing base (base output is 8V 200mA).

The unit is perfectly usable but the batteries are old and losing the ability to hold a charge, rendering the vacuum essentially useless. I would like to simply replace the old batteries with new consumer-grade rechargeable AA NiMH (Panasonic Eneloop 1.2V 1900mAh) ones.

Question 1: Is it correct to assume that all rechargeable AA NiMH batteries charge at the same voltage and current, and that replacing one brand of battery with another should be safe to use with the original charging base?

Question 2: Given heat caused by charging, etc., is it reasonably safe to stack the new batteries by hot-gluing the bodies together?


texts:
I am trying to design a band pass filter that allows frequencies between 16,384Hz and 32,768Hz. Firstly I tried to make it using a passive RC band pass filter:

Using the formula fc = 1/2πRC, the filter should work as I expect, but the result is far from being what I want. This is the result after an AC analysis:

The cutoff frequencies are: 7.1KHz and 71KHz at -9dB, the peak value of the gain is -6dB so I presumed that at -9dB are the cutoff frequencies.

What is even stranger to me is the fact that if I divide the circuit in two filter, a high pass filter (left side of the circuit) and a low pass filter (right side of the circuit), it works perfectly fine, both frequencies under 16KHz and above 32KHz are rejected.

Is there any solution for this circuit or an alternative circuit such a filter with this bandwidth?

Thank you!


texts: How is the Second level of Cache Accessed

texts:
Since the processors have more than one level f memory, how is the 2nd level of Cache accessed.

i.e.,

Access both the first level of Cache and 2nd level are Cache are accessed at the same time. If it is a hit in 1st level then it may stop searching in the 2nd level. Disadvantage is higher power dissipation
Second level of cache is accessed only after the miss of first level. So the time of getting the data is more and the processor performance may drastically decrease if the first level of cache is a bit larger


texts: How does pseudo-random noise increase DCF77 accuracy

texts:
A few years ago the Germans added a pseudo-random noise signal (from a LFSR) to their time reference DCF77. I heard this should allow you to get a more accurate signal at the receiver side. But the signal delay due to the distance (up to 2000 km) and due to the electronics is the same for the basic AM signal as for the pseudo-random noise, isn't it?
How can I use the added pseudo-random noise?


texts:
My question involves chassis grounding to earth ground.

My PCB circuit is a simple signal generator using a microcontroller. It has a separate 'ground' from earth ground, supplied by a floating 5VDC source. (I guess we would call this a digital ground?)

The PCB is to be installed inside a metal chassis (aluminum, I believe). Inside, there is a 15VDC converter. As a signal generator, it outputs a signal with reference to the +5V.

Unfortunately, the device that uses this output signal is grounded to the earth ground, not the digital ground.

The signal, which is supposed to drive a motor, ends up having severe noise problems.

What I found out was that if I provide the chassis (not the circuit ground) a capacitative ground to the earth ground by connecting a capacitor from the chassis to the earth ground pin, the noise problem disappears. However, if I connect the earth ground DIRECTLY to the chassis, the circuit is shorted.

So my question would be, is it normal/safe to ground the chassis of a circuit with digital ground using only a capacitor? If not, is there a better way to fix the noise issue?

Also, even with the capacitor to the earth ground, whenever a large machinery sharing the same earth ground turns on, my device shorts for an instant, and resets the microcontroller. Is this caused by a large current draw from the big machinery? But how so, if only the earth ground is common?


texts: How to select appropriate capacitor for an H-bridge

texts:
PROBLEM: Considering the figure below, I need to select an appropriate bank of capacitors for a 3 half-bridge brushless controller, which system have this characteristics:

VM = 60v (maximum);
Max Current = 100A;
PWM frequency: 100khz;
Rds(on) typical is 1.15mOhm;
Rshunt = 1.0mOhm.

QUESTIONS:
1- What SMD package is recommended to use for these capacitors? (I'm considering to use 1206 or 1210)
2- For the capacitance, the higher the better?
3- For the number of capacitors, the more the better?
4- How to calculate a proper C for the capacitors?

LAYOUT INTENTIONS:
The bulk caps will be placed as shown below, in order to get the minimum current loop:
Top Layer:

3D View from Top Layer:


texts:
How would you go about showing the concatenation of two buses in a schematic (preferably KiCad or Eagle).

For example suppose a component has z as an input, where z is 32-bit. Suppose z is fed by a concatenation of bus signal x which is 16-bit, and bus signal y which is 16-bit.

How would you draw signals x, y, and z in the schematic?


texts:
I have been designing some two input XOR-XNOR circuits using Cadence Virtuoso. All of them are working as expected but there is a little problem when both the inputs make a transition; the XOR and XNOR outputs encounter a peak. Consider one of those circuits shown below.

The XOR and XNOR pins have been already marked. The output is shown below.

So when A goes from 0 to 1 and B goes from 1 to 0, both XOR and XNOR encounter a dip and a peak respectively, which should not be the case. I am not able to understand why this is happening. I think that it is due to some delays in the MOS, but that reasoning is not sufficient. Any help is appreciated.


texts:
I'm not an electrical person, and need to identify the type of wiring used on my Asus adapter for my router.
Beneath the outer insulation is a set of copper bindings that wrap a white insulation layer with another copper wiring in the middle.
Screenshot:

I need to fix this cable, however, have been told that it's not possible.


texts:
simulate this circuit – Schematic created using CircuitLab

I am analyzing work of amplitude limiter built on transistor, and I can see an incoherence as far as rising times for different frequencies and input voltages are concerned. The problem is: the bigger voltage on input for 1kHz is used, the longer rise time is, but the bigger voltage on input for 30kHz is used, the shorter rise time is. Are my measurements wrong?

I know that theoretically rising time for square wave equals 0, but what is the relation between rise time, frequency and input voltage?

Here are the oscilloscope output photos:

1: 1kHz 2V
2: 1kHz 5V
3: 30kHz 2V
4: 30kHz 5V


texts:
Are high capacitance electrical capacitors capable of storing energy instead of using a battery.
If so would they be able to hold 7 kws of usable energy for domestic home use?


texts: How is this source actually connected in the circuit?

texts:
I have seen this way of connecting the source in a couple of books now but I still am not sure if I am getting it right.

This is how I am interpreting it, I have a feeling I'm very much wrong.
The original picture is taken from The Art of Electronics. Thank you!


texts:
I've a problem to choose correctly which Crystal to use with an ARM Cortex M4. In particular, I can't understand relationship between datasheet specifics and a Crystal used in an ARM Cortex M4 EVB.

Here's schematics of ARM Cortex M4 EVB crystal (Crystal used is FQ5032B-12-C-C-C-200-1 Datasheet: http://www.mouser.com/ds/2/160/fq5032-9986.pdf ):

And here's datasheet regarding crystal specifics with this type of MCU:

I can't understand why is calculated Cext as 20pF but used 18pF. Also, Max. Allowed Crystal Capacitance Load is 17.5pF and in this EVB is used 20pF, why? And which problem it can generate(I found it can generate Freq. Drift)?


texts: How can software determine the amount of power or charge left in a battery (like an iPhone battery or a laptop battery)?


texts: VHDL test bench for input port assignment

texts:
I am trying to depict port 3 of microcontroller which acts a I/O and as special functions like timers interrupts in VHDL.

The code is as follows:

    library IEEE;
    use IEEE.std_logic_1164.all;
    entity testIO is
    port (
    p3: inout std_logic;
    op:out std_logic;
    r0:in std_logic;
    sel_line:in std_logic;
    T0:out std_logic;
    Clk    :  in std_logic;
    ip:in std_logic
    );
    end testIO;
    architecture beh of testIO is
    Begin
    process(clk)
    begin
    if Clk'event and Clk='1'then
    if r0 = '1' then
    T0 <= p3;
    else
    p3 <= 'Z';
    end if;
    if sel_line = '1' and r0 = '0' then
    p3 <= ip;
    else
    p3 <= 'Z';
    end if;
    if sel_line = '0' and r0 = '0' then
    op<= p3 ;
    else
    p3 <= 'Z';
    end if;
    end if;
    end process;
    end beh;

My testbench is as follows:

    library IEEE;
    use IEEE.STD_LOGIC_1164.ALL;
    entity testIO_tb is
    end testIO_tb;
    architecture Behavioral_tb of testIO_tb is
    component testIO is
    port (
    p3: inout std_logic;
    op:out std_logic;
    r0:in std_logic;
    sel_line:in std_logic;
    T0:out std_logic;
    Clk    :  in std_logic;
    ip:in std_logic
    );
    end component;
    signal p3_s,sel_line_s,T0_s,ip_s,op_s: std_logic;
    signal r0_s:std_logic:='1';
    signal Clk_s:std_logic:='0';
    begin
    DUT1:testIO port map(
    p3   => p3_s,
    op   => op_s,
    r0   => r0_s,
    sel_line => sel_line_s,
    T0   => T0_s,
    Clk   => Clk_s,
    ip   => ip_s
    );
    Clk_s <= not Clk_s after 5ns;
    process
    begin
    if r0_s='1' then
    p3_s<='1';
    else
    p3_s<='Z';
    end if;
    wait for 10ns;
    r0_s<='0';
    sel_line_s<='1';
    ip_s<='0';
    p3_s<='Z';
    wait for 10ns;
    sel_line_s<='0';
    wait for 10ns;
    end process;
    end Behavioral_tb;

In the simulation,the value of p3 is not set to '1' at 0ns though I am setting it to 1 in testbench. It is setting to 1 at 5ns.  I am not sure why.

Also T0 value is not getting updated at 5ns and ip value is not copied to p3 at 15ns.


texts: Is it harder for a low-battery DMM to measure current in a comparison to measuring voltage and resistance?

texts: My DMM is doing a good job in measuring voltage and resistance but when I measure currents I get 0 readings. Is it possible that having a weaker battery affects only current measurements/ If so - why?


texts: Power impact in a wireless sensor network architecture

texts:
this is not a real question but a way to talk about the following topic.
I was thinking on a monitoring system based on a Sensor part, a Computing part and a Radio Transmission part.

My question is how much is the power impact of the radio part compared to the power consumption of the sensor part or the computing part?
If I want to answer myself I think it depends on the specific Radio tecnology consumption in idle state or active, the sampling rate, the type of sensor I want to use, if I use a microcontroller based unit or a microprocessor one.

Am I right? What can you tell me more about this? Any good book or article to read about this topic?

Thanks ;)


texts: Resistor and Incandescent Lamp in Series

texts: I’m new to electronics and am trying to ground myself in basic concepts.  On my test circuit board I have a 5.08V power supply, a 200 ohm resistor and a 1.5V incandescent lamp in series.  The voltage drop over the resistor measures 5.05V and the voltage drop over the lamp measures .02V.  The current measures .02A.  Why doesn’t the lamp have more voltage available to it? Thanks!