texts: Understanding a Hardware Description Language, circa 1965

texts:
This question is on the fence between RC and EE; as the design style is half a century old, I decided to ask the RC audience first.

Back in 1965, Soviet computer developers used a rudimentary HDL in the manufacturing documentation. Bitwise combinational logic looked quite understandable,  with · for AND, + for OR, and an overbar for NOT.

The registers, however, were defined in a more cryptic way.

For example (converting Russian abbreviations to English but keeping all other notation as is for authenticity), a typical bit of the accumulator in the middle of the mantissa was defined as

14bRxAcc = C·[ShREn·15bRAcc + HoldEn·14bRAcc + ShLEn·13bRAcc] +
             [ShMant4En·18bRAcc + ReplEn·14bNextAcc]·C
14bRAcc = K·14bRxAcc

RAcc and RxAcc are the arrays of stored bits of the accumulator
ShREn, HoldEn, ShLEn - shift right enable, hold enable, shift left enable
ShMant4En - shift mantissa by 4 bit enable, ReplEn - replace enable
NextAcc - the new value of the accumulator
C and K are the opposite phases of the clock signal.

Splitting the RxACC assignment into two ORed clauses expresses the limitation of 3 OR clauses per standard element.

Here we can see the sequential left and right shifters, and a faster (4 bit positions per clock cycle) mantissa shifter, plus assigning a computed value of the bit.

However, if we rewrite this to zero-delay Verilog

assign RxAcc[14] = C & (ShREn & RAcc[15] | HoldEn & RAcc[14] | ShLEn & Racc[13]) |
                   (ShMant4En & RAcc[18] | ReplEn & NextAcc[14]) & C;
assign RAcc[14] = K & RxAcc[14];

it will not work, because at any moment either C or K is zero.

It should be noted that the design was static; it was possible to single-step the CPU from the console.

My question is, what would be the corresponding Verilog definition of RAcc and RxAcc, taking into account that both of them could be used by the combinational logic?

Is it safe to assume that whenever C or K is mentioned in a formula, the expression should be taken as a latch rather than an AND gate?


texts:
I want to pass some data from my verilog to my microblaze core in ISE 14.7.  I was doing some research and it seemed like the FSL was the easiest way to go about this.

What I did was create a peripheral with one 32b input and one 32b output of the FSL variety.  I then clicked configure coprocessor and added my new fsl_link to it.

That done, it added fsl_link_0_to_microblaze_0, microblaze_0_to_fsl_link_0, and fsl_link_0 to my Bus Interface window.

I then did a DRC check and I get

ERROR:EDK:3900 - issued from TCL procedure "::hw_fsl_v20_v2_11_f::check_syslevel_settings" line 14
fsl_link_0_to_microblaze_0 (fsl_v20) - FSL_Clk is unconnected.

ERROR:EDK:3900 - issued from TCL procedure "::hw_fsl_v20_v2_11_f::check_syslevel_settings" line 14
microblaze_0_to_fsl_link_0 (fsl_v20) - FSL_Clk is unconnected.

All I want to do is pass some register values from my verilog to my uBlaze (doesn't even need to go the other direction for now).  What am I doing wrong?  I am not sure how I need to set up the clocks by my FPGA runs at 200MHz and my uBlaze is clocking at 100MHz if that helps.


texts: How to avoid this voltage when I turn on the circuit?

texts:
What I want to do is an Delay ON, but when I press the switch this voltage pass for a brief moment and turns the led on for a moment.

How can I avoid this?
Should I put the switch somewhere else?

If you can make another suggestion for a circuit I wold be happy to read it, what I need is that the led  come on only  if the switch is on continously for more than 13 seconds.

Thanks in advance.


texts:
Using an ATTiny85 and an Arduino loader I created a simple device for turning on an exhaust fan based on a light sensor.  The ATTiny85 turns on the fan after activating a warning light and sounding an alarm.   Of course, I use a relay to amplify the signal from the ATTiny85 to switch the AC power to the fan.  I’m not using I2C, it is simply an on/off pin command.  All well and good.

However, after several weeks of operation the ATTiny85 seems to increase its clock speed.  The warning light flashes much faster than it was programmed to and the alarm sounds for a shorter time and at a higher pitch.

digitalWrite(FUNCTION, HIGH);
buzzer(1000, 1, 1);
delay(700);
buzzer(1000, 1, 1);
delay(700);
buzzer(2000, 1, 1);
fan(ON);
digitalWrite(FUNCTION, LOW);

Simply rebooting the system solves the problem for a few weeks.

Initially I figured the problem was dirty power.  I replaced the 5V transformer running the chip with a 12V transformer and ran the power through a XL4015 Step-Down Buck Converter.  When I test the power going to the ATTiny85 from the buck, I get a steady 5.16V as designed.  Still, after a few weeks, the ATTiny85 seems to go into hyper-speed.

I have searched along the lines of “ATTiny85 clock speed” and have found nothing that approximates my problem.  The code is a fairly simple loop and the integers passed to the "buzzer" routine should produce a constant time period, I would think.

Assuming the code is not at fault, are there ways that the ATTiny85’s clock speed can be altered by external events?  Power spikes? phases of the moon? ;-)...

I wanted to ask this question, before I go wading-in looking for a silly software bug!  Which is likely the problem!

Awjlogan and SamGibson - Thanks for your prompt reply and suggestions.
Your initial comments about Protection Circuitry and Vdd ramp-up “inspired” me to look at:

EEVblog #859 - Bypass Capacitor Tutorial
https://www.youtube.com/watch?v=BcJ6UdDx1vg

When I built this little project I had just gotten a new cable crimper.  A PA-09 and it works great for making custom Dupont connectors.  After going thru Dave’s blog I suspect I over did it.  The leads are at least 150 mm long.  More than enough to cause problems.  I’m betting that these long connectors and NO Bypass Caps are the reason I’m having problems!  Naively, I thought that the XL4015 Step-Down Buck Converter would have taken care of this.  But based on what I’ve learned the length of the connectors are probably the source of the problem.

I’ll update this post when I’ve confirmed or denied this assessment.

Thanks for your input!


texts: I connected two ends of battery with copper wire, and nothing happened. Why?

texts:
I'm trying to build a simple motor with the help of some youtube tutorials but nothing seems to spin... so I figures ok let's connect the ends of the battery and see if that the problem. If I get electrocuted then everything is all right lol. I tried with 2 batteries and nothing happened...
Does someone have an idea what the problem might be? I'm using a 1.5V battery, is that maybe too little?

The wire isn't isolated, so I really have no idea what the problem is.


texts: How dead time happens in boost converter?

texts: I understand that in a buck converter dead time happens as both switches are ON simultaneously and this short the power supply. However, I don't see how dead time can exist in boost converter. Could anyone explain it?


texts: How can I design a double pole eight throw microwave (2-6 GHz) switch?

texts:
I need to design a DP8T microwave switch for a microwave imaging senior design project. The frequency range is 2 to 6 GHz.

I need to switch between 8 antennas and a 2 port VNA. So each antenna transmitting and receive one at a time. I'd imagine this is a common problem in RF engineering, but I can not find an IC chip or a commercial solution that is 2X8.

Switching time: Doesn't matter

Power: 16 dBm

Insertion Loss ~ .8 dB

Isolation > 30 dB

Control signal: TTL or CMOS

Above all, I will settle for anything that can work. I want to have a start at something even if I can improve later. My budget is very limited, even though I have access to PCB printing and lab equipment.


texts: How to make a cable to record cockpit intercom?

texts:
I would like to record the cockpit intercom with my iPhone and a recording app.  I do not know much about impedance matching (other than what it is).

I would like to make a cable that plugs into the audio out jack to my headset and has an output to a 3.5mm jack as well as a pass-through wire so I can still use a headset.

I would like to make one of these, but I'm not sure what sort of resistors they are using inside of it.

I can tell you that the impedance of the headset is 600ohms, which means that the signal going to them has a very high voltage that I need to step down before I can record it with an iPhone.

I'm sorry for the lack of information or experience, but I do not want to blow $40 on a cable that should cost $3.


texts: Which method is best method to amplify 3.3 v output to 10 v to drive MOSFET Switches with Low RDs ? NPN transistor or DC-DC boost Converter?

texts:
Iam using STM32F401 microcontroller to drivie mosfets for bidirectional current control for safe charging and discharging operation of a Battery pack.

My microcontroller maximum PWM output to drive mosfets are 3.3v . i would like to amplify 3.3v to 10v to drive the mosfets with low Rds for power consumption.

So when i search in internet i came up with two results to amplify 3.3v to 10v . one is NPN transistor common emitter configuration. another is DC-DC boost converter.

I would like to know which is the best method to amplify 3.3 v to 10 v to drive Mosfets.

My Circuit:

In the above circuit i have used NPN transistor just for an understanding and completion of the circuit.

but I would like to know which method is best and efficient to use DC-DC boost converter or NPN Transistor


texts: Counting PIC18F46K20 internal clock edges using MPLAB C18?

texts:
I am trying to create a countdown timer using the PIC18F46K20 and display the time on the OLED. I have set up TIMER0 to create a delay of 1 second ( T0CON = 0b00000001 ) so the variabe intCLKsecs should increase every second.

    Timer0_Init();          //Initialise timer
T0CONbits.TMR0ON = 1;  // start timer

while(INTCONbits.TMR0IF = 1) {

/* Check for clock edges and and increment countSecs by one on every falling edge.
   The timer is set up to output pulses that are around 1 sec apart.
*/
        INTCONbits.TMR0IF = 0; // Clear the flag

    korf_intCLKsecs++; //Should increase by one every second on every falling edge
    korf_InitSecs = 1800; //Initialised time for a single korfball half
    net_timeLeft = net_InitSecs-net_intCLKsecs; //Time remaining in the half
    displayTime(net_timeLeft);

}

I pass the the [timeLeft] to a function that formats it and displays it like a clock i.e 8:56 Here is the time dicplay function.

int displayTime(int currentTime)
{
    int secs;
    int mins;
    char Buffer[60];
    secs =  currentTime % 60;
    mins = (currentTime / 60) % 60;

    sprintf(Buffer, "\n\t\t %d : %d\0",mins,secs);
    oled_puts_1x(Buffer);
    oled_refresh();
    oled_clear();
}

I do apologize if i have made any mistakes in the way i am posting, I am very new to both forums and PICKit programming.
Can someone out there please help me figure out how to get a correct value into my intCLKsecs variable by counting the CLK pulses on every falling edge? What do i write in MPLAB IDE to make sure that [intCLKsecs] increases on every falling edge?


texts: raspberry pi 3V LED. What resistor to use?

texts:
I will connect this button with a 3V LED to RP3. what resistor should I be using ? Do not know the amperage of the LED.

https://www.amazon.co.uk/sourcing-map-Momentary-Button-Mounting/dp/B07FYSR7Y7/ref=sr_1_6?keywords=Push%2BButton%2BSwitch%2B3v&qid=1565432578&s=diy&sr=1-6&th=1


texts: AQH3223 does not turn off, even though there is no trigger voltage

texts:
I'm trying to design a computer-controlled power ON/OFF system for the device I'm working on. what I need is that I can turn device on or off with computer, and I have the means to apply 5v digital output from my computer (by using a DAQ). I found something about AQH3223 on the internet and bought the IC, tested it initially, and designed my PCB. But it seems like I tested it sloppy, because the device turns on, but does NOT turn off. I apply digital trigger to Power ON pins (pin 2), the input supply goes in pin 8 (VCC-IN), and is feeded to my device from pin 6 (VCC). Also, I have positive and negative supply voltages, thus the double design.

Now like I said, when I apply trigger, both SSRs work fine and turn on, but when  I put it off (by turning digital output to zero) they're still on. I even tested the ICs on breadboard (this time thoroughly), and got the same result. I apply 5v to trigger and an input feed to pin 8, and a LED is connected to pin 6 that is grounded. this time, the LED is always on unless I take down the feed voltage on pin 8. I also did some search and found this topic Triac BTA316 does not turn off but they didn't find any answer either.

is there an easy fix for this? or better, another way to do this turning on and off?
thanks.


texts: Read and Write file from SD Card with fpga

texts:
I'm working on a simple project with Quartus in which I've tried to implementent a NIOS II processor for read from and write to a SD Card.
Here it is the schematic

The C code is
#include <stdio.h>
#include <system.h>
#include <altera_up_sd_card_avalon_interface.h>
short int sd_fileh,sd_fileh2,att;
char buffer[512]="WELCOME TO THE INTERFACE!!\r\n\0";
char data[512];
int i,pixel,att3;
int main()
{

    printf("SD Card Access Test\n");

       alt_up_sd_card_dev *sd_card_dev=("/dev/Altera_UP_SD_Card_Avalon_Interface_0");
       if(sd_card_dev !=0)   //Checking if the card is present
           {
              if(alt_up_sd_card_is_Present())
              {
                if(alt_up_sd_card_is_FAT16())  //Checking if is FAT16
                 printf("Card is FAT16\n");
                else
                 printf("Card is not FAT16\n");
                sd_fileh= alt_up_sd_card_fopen("test1.txt",true); //Creating a new text file and writing data on it

                if (sd_fileh<0)
                 printf("Problem creating file. Error%i",sd_fileh);
                else
                {
                 printf("SD Accessed Sucessufully,writing data...\n");

                 int index=0;
                 while (buffer[index] !='\0')                    //Write the data in the buffer to the file
                 {
                    alt_up_sd_card_write(sd_fileh,buffer[index]);
                    index = index+1;
                 }
                 printf("Writing done!\n");
                 printf("Closing file 1...\n");
                 alt_up_sd_card_fclose(sd_fileh);
               }

 //*****reading text file***********

          sd_fileh2=alt_up_sd_card_fopen("test2.txt",false);

          if(sd_fileh2<0)
             printf("Problem creating file. Error %i",sd_fileh2);
          else
          {
             printf("SD Accessed successfully,reading data...\n");
             printf("Data read fromthe text file = \n");
             for(i=0;i<12;i++)
             {
               data[i]= alt_up_sd_card_read(sd_fileh);
               printf("%c",data[i]);
              }
             printf("\Closing file...");
             alt_up_sd_card_fclose(sd_fileh2);
             printf("Done\n");
           }
        }
     }
     return 0;
}

With altera monitor program I start the program but it stops at the first printf. What is wrong?


texts:
I read on many books this formula to calculate the quality factor of a series between a resistance and a reactive component (L and/or C):

Now let's consider the series between a resistance and a capacitance:

In this case the capacitive reactance is equal to -1/(ωC), so according to the previous formula, Q should be negative. But everywhere it is written as a positive quantity. So my question is: should the formula in the first picture have the absolute value? So Q = |X|/R?


texts: I've made a really primitive spectrophotometer using an RGB LED and a transimpedance amplifier, and I'd like to fine tune it a bit. Most importantly, I was wondering if it was possible to map RGB values to a specific wavelength so that I could graph output voltage values against wavelength values. I found this online tool: Link here, but I'm not sure if it's accurate for an LED. Also, I found that most colors appear uniform with the LED, but mixing equal red and blue is always distinctly red and blue; i.e., it doesn't appear purple. Any suggestions/input?


texts: Trying to remove distortion of speakers seems impossible

texts:
I'm working in a project with the goal of make a portable bluetooth speakers without distortion.
When I try to turn up the volume, the speakers start to make a distorsion, like when rhe radio can't get the correct frequency.p

In the project, I use a 3×2 PAM8403 amplifier in a tiny module, 1× 7805 and a 2N60B transistor (I asked in another forum for this problem, and they answered I have to use the transistor if I want to get more amperes and remove the audio distortion) and two speakers (4Ω, 5-8W).
The amp is powered by 5 volts generated by the 7805 from a 9V battery.

I searched around the web by 3 months. Different answers and any of them works.

I hope some of you could help me removing the distortion definitely, I've been working on this project since the past summer.

Schematic


texts: is stm32f103 programmable via micro usb?

texts:
I would like to buy following thing to start. I've got tired of arduino and after some research I came across this.

STM32f103

I am wondering what do I need to start programming this board? Is it programmable over micro usb or do I need JTAG cable. Also is there some good starting tutorials for it, cause I haven't found any?


texts: Does the electrical load on a generator affect its mechanical resistance?

texts:
If you take as an example the alternator on a car. Say the engine is set to idle at 1000 rpm. The resistance of the engine itself and any accessories it is driving require a certain amount of gas to maintain 1000 rpm. Now assume the alternator at idle speed can provide 1000 watts of power, but keeping the battery charged and running the engine is only pulling 100 watts. (I have no idea if these numbers are realistic. I'm just using it as an example.) Then if you use the alternator to to power a 900 W device, so now you're pulling the full 1000 W potential, does the mechanical resistance of the alternator increase, thus requiring slightly more gas to maintain 1000 rpm?

If so, what causes this? The electricity is being generated by passing coils through a constant magnetic field. The potential output is limited, I assume, by the rotational speed. Does it matter how much current is load it actually has at that speed? Or is any excess potential simply wasted.

This might be a duplicate but I couldn't find an answer that made sense to me.


texts: How to connect PWM output from a dsPIC MCU to 12V LEDs?

texts:
How to connect PWM output from a dsPIC30F MCU channels to 12V LED diodes? 4 x PWM channels will be used. For use with following voltage:

12V 5A Power Supply
1W high-power LEDs with working current 350mA (4 banks of 1 watt LED's)
Overcurrent protection on output of each channel.

And another setup, same as above, but for Operating Voltage range 9-27V (for use 12V or 24V LED's, either type)

What is be better to use, MOSFET transistors, example IRF8313, or Darlington Transistor Arrays, example ULN2803A?

LED connection diagram like: :


texts:
I've been daisy chaining power strips and it was no issue until my friend told me it's dangerous. I was using 2 monitors, fan, desktop,55inch TV, monitor speakers, and a phone charger.

And he told me it could be more dangerous in the future as I will add more stereo speakers and amplifier.

However, my dad on the other hand said it is a no issue at all as all my appliances are not demanding in power. Who should I listen to?


texts: multi turn potentiometers to measure degrees

texts: I want to display  degrees in a seven segment display when rotate multi turn potentiometers.After rotating one round it should be reset to 0 degree.I can use A to D converter ICs.But how I give voltage signal to it when potentiometer rotates after one round.


texts:
I'm reading the document "Eddy Current Losses in Transformer Windings and Circuit Wiring" by Lloyd H. Dixon, Jr about proximity effect in transformer and more generally. I have a misunderstanding point. Here it is:

Fig. 5 - Circuit Wiring - Flat Parallel Strip  "Eddy Current Losses in Transformer Windings and Circuit Wiring" by Lloyd H. Dixon, Jr

As the current direction in the two strips is opposed, the magnetic field is very high between the two strips as each magnetic field of each strip adds each other. Nevertheless, according to Faraday's Law and Lenz's Law, I do not understand why the eddy current are not maximum at the place where the magnetic fields is maximum. Hence if the eddy current is maximum at this place, the eddy current being opposed to the current flowing into the conductor, the current should be lower at the place where the magnetic field is maximum?

The eddy current is flowing such that it enhances the magnetic field produced by the main current. It is in contradiction with the Lenz's Law and physically this is not possible because I do not understand where the equilibrium is reached. Please bring me to the light !

Lenz's Law = "the direction of the current induced in a conductor by a changing magnetic field is such that the magnetic field created by the induced current opposes the initial changing magnetic field."

Thank you very much.


texts:
Sorry if this is a basic question. I would like to use photodiodes to precisely measure changes to light amplitude using an Arduino, similar to Figure 2 here:

However, I would like to wire six photodiodes using a common 5V input and ground, so that wiring is minimal and the measurements occur simultaneously. Does anyone know how I could do this?


texts: Difference between data retention in flash and in EEPROM

texts:
In a security recommendation (Mobile Operating System Protection Profile, §4.2.1 FCS_CKM_EXT.4.1), the following instructions are given to securely wipe a cryptographic key from memory:

  For non-volatile EEPROM, the zeroization shall be executed by a single direct overwrite consisting of a pseudo-random pattern (…).
  For (…) non-volatile flash memory, the zeroization shall be executed by a single direct overwrite consisting of a single direct overwrite with zeros (…).

In plainer English: you can erase data in flash by simply zeroing it, but for EEPROM you must overwrite with a random pattern.

I have no other information to infer what difference between EEPROM and flash is meant. I guess the technologies would be the ones in typical smartphones since this is the type of device that this security document addresses.

What is different between overwriting data in EEPROM and overwriting data in flash memory, that would explain the different requirements?

[Related: Where do these rules come from?]


texts: What is the name of this component? 2 pin, white connector

texts:
I need to buy the male side of this pictured component.
It is in a Kokoon moon door bell, and is white with 2 pins.
From hunting around, it could perhaps be a 2.54mm JST-XHP JST connector. I purchased a dupont type kit, that wasn't it.

How do I tell?
Could you give me some guidance on identifying it, so I get the right attachment?


texts:
I've been reading an article (TheMagPi eMagazine) relating to the Raspberry Pi; "An ARM GNU/Linux box for $25."

In the article, page 17 at the bottom it shows an area on the Pi where a track zigzags next to a straight one with the explanation text:

  The “wiggles” in tracks, ensure signals are matched  electrically,
  reducing interference and signal delay.  This is particularly
  important for high speed video  data and HDMI signals.

I have very limited knowledge of electrical engineering so perhaps this is a very simple question but why would you incorporate these 'wiggles' in a PCB design?

I realise the quote gives me an answer and I sort of understand the interference point due to problems with power cables and coaxial cables running next to each other but I'd appreciate something assuming very little knowledge that explained why you would get the problems and how wiggles help. For example, why isn't the board covered in wiggles?


texts: Arduino FFT on data received from current sensor

texts:
I'm working on a project of a predictive maintenance application, where I would like to sample an alternate 50 Hz current by sensors based on the Hall effect (such as ACS712 or any sensors with a clamp and where the AC signal is converted into analog voltage).
I'm using an Arduino 10 bit analog resolution of the SAMD21 processor family (48 Mhz).
The alternate current is 50 Hz. The method should be to get multiple frequency spectrum 'snapshots' by the sensor and through the ADC, by the use of FFT or STFT.
We want to investigate the spectrum of current readings induction motors in the frequency domain, at steady state (different load conditions also) and especially at start-up transient phase (the first 2-3 seconds).
The dominant frequency is 50 Hz (alternate current EU).
We have found some libraries that are able to do a frequency analysis by FFT on the Arduino itself.
However, we would really appreciate any advice from you or suggestions about the correct or best sampling Frequency and sampling Rate for an alternate current 50 Hz.
Thanks really for any help.
MC


texts: Can somebody explain discrete time frequency

texts:
I am an analog guy learning DSP, and I am a bit confused by discrete time frequency.

What units is discrete time frequency k measured in?

I have read that k is the index of the frequency and not the frequency itself. Not sure what this statement means.

For example if I have a 100Hz sine wave sampled at 44KHz and a total sample length of 10 seconds, what is it's discrete time frequency?


texts: how to get the timing report register to register and input to output in STA?

texts:
I'm trying to get the timing report of STA. As I know, basically, there are 4 types of timing paths.

Input to register

Register to register

Register to output

Input to output

Practically, I want to know what command do I need to get the 4 timing reports?
So far, I know how to make 2 paths:
report_timing -from [all_inputs] >report_from_all_input.txt

report_timing -to [all_outputs] > report_to_all_output.txt

but the other things not.
Would you help me how to get the timing report of 4 paths in Design Compiler?
update
I come across the below message when I run with below command.
report_timing -from [all_inputs]    -to [all_registers]  > report_input2reg.txt
report_timing -from [all_registers] -to [all_registers]  > report_reg2reg.txt
report_timing -from [all_registers] -to [all_outputs]    > report_reg2output.txt
report_timing -from [all_inputs]    -to [all_outputs]    > report_intput2output.txt

-output
Warning: cell 'u_phase_sub17/p_reg[6]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[8]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[9]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[10]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[11]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[12]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub17/p_reg[13]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub8/p_reg[3]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub8/p_reg[4]' is of the wrong type. (UID-119)
Warning: cell 'u_phase_sub8/p_reg[7]' is of the wrong type. (UID-119)
Warning: ...13357 additional objects are of the wrong type. (UID-119)
Warning: Ignoring all 13367 objects in collection '_sel29' because they are not of type pin, port, net, clock, or ge
Error: Value for list '-from' must have 1 elements. (CMD-036)
0

Did I use that commands correctly? I only expected it to make bunch of the below timing lists.
  Startpoint: i_f0[2] (input port clocked by clk)
  Endpoint: trad_28_reg[68]
            (rising edge-triggered flip-flop clocked by clk)
  Path Group: clk
  Path Type: max

  Point                                    Incr       Path
  -----------------------------------------------------------
  clock clk (rise edge)                    0.00       0.00
  clock network delay (ideal)              0.00       0.00
  input external delay                     0.10       0.10 f
  data arrival time                                   7.41
  ...
  clock clk (rise edge)                    7.80       7.80
  clock network delay (ideal)              0.00       7.80
  clock uncertainty                       -0.05       7.75
  library setup time                      -0.05       7.70
  data required time                                  7.70
  -----------------------------------------------------------
  data required time                                  7.70
  data arrival time                                  -7.41
  -----------------------------------------------------------
  slack (MET)                                         0.29


texts:
I want to measure both voltage and current from an output expansion port, of the BeagleBoard-xM. I managed to measure voltage by putting measuring lead (red) to the expansion port and reference lead (black) to ground.

How can I measure current of the expansion port, without shorting it? Should I transfer current to a breadboard and taking the measurement somehow from there?


texts:
I have an ADC circuit which uses AD7689. The inputs of the ADC are driven by LT6010 opamp, and have a low pass filter .

All 8 channels of the ADC (AD7689) have the same driving circuit. Every other input of the ADC always shows a 3.1mV signal whenever a full scale voltage is applied to the adjacent channel. For example when I apply 5v to channel 1 and short channel 2, channel 2 will read 3.1mV, and all other channels will show 0v. Similar thing happens with channel 3, and 4, and so forth. Now if I remove the capacitor (C152) which is part of the RC filter this problem goes away, and the adjacent ADC input fluctuates between 0.1mV to 0.5mV. An input on channel 1 only effects channel 2. Another thing I noticed was that if I read these channels with longer delay then I don't see this problem. Like If i wait 800 microseconds after reading channel 1, I won't see 3.1mV on channel 2. Is RC filter designed wrong


texts: Understanding gate threshold voltage of logic level mosfets from datasheet

texts:
I want to build an Arduino Project to control a DC load(DC 5V water pump ampere rating is not known) and using a transistor with PWM to control speed. There is a need to shrink down the project and I have chosen Digistump ATTiny85. But read that Digistump board can't source enough current in the transistor to turn it on. An extensive search reveals people suggesting to use a logic level MOSFET instead for the purpose.
Even Digistump sells a MOSFET shield which has a logic level MOSFET(FQP30N06L). But this part is unavailable in nearby stores.
I am trying to read the datasheet of other available MOSFET(STP90NF03l) and understand whether it would suffice my purpose. What should I look for in the datasheet?
Digital IO pins in Digistump outputs 3.3V-5V. So the voltage threshold for the MOSFET to turn on would be less than 3.3V line(~2.5V say) so that I may test it with both my Arduino and Digistump board.


texts: How Johnson measured Johnson-Nyquist noise?

texts: How Mr. Johnson, the one after which Johnson–Nyquist noise was named measured/discovered this phenomena? Details about equipment and method are most welcome.


texts: Long transmission line inductance with SPI

texts:
I have a PCI 5V GPIO card which bit-bangs SPI over a 10-foot cable. The SPI clock is running at 800Khz. The cable connects to a board and the SPI lines feed directly into the SPI IC's. I know SPI is a short, board level communication, but I can't change any of that going forward.

When I looked at the SPI clock and MOSI lines, I was seeing a 12V pulse on rising/falling edge that lasted for about 40ns. That tells me there is significant transmission line inductance. I can't change anything on the PCI card/cable and I am not able to slow down the drive strength of the line. I tried adding 100 ohms series resistance on the board side, but that had no effect since the inductance is still between the drive and the series resistor. An RC filter on the board side of 100 ohms, 1nF also had little effect.

My next step, is to add an IC buffer that can handle the spikes and not pass them through. I just wanted to see if anyone else had a suggestion or could recommend a good IC buffer.

Thanks.


texts: I have a number of Vg vs Id data sets/plots for a transistor under a number of different conditions that I need to extract the subthreshold slope from but I am not sure the best way to do it.  I have done some rough hand calculations subtracting a gate voltage from another over a decade of drain current change in the subthreshold region but I am looking for a more precise way of doing it.  Is there a good algorithm for calculating the subthreshold slope from a .csv file of data points?


texts:
I am trying to recall the quick way to check the EM polarization theoretically, I mean if I have a wave described as (ssume capital letters are vectorial fields)

\begin{equation}
\ E = E_o *exp(j* \varphi)\\
\ E_o = E_r +j*E_i\\
\end{equation}

I recall that there were an easy math check to verify the kind of polarization that the EM wave had, however I am not completely sure about whether the vector/cross products are as showed below or not, could anyone remind me a bit?

Lineal polarization

\begin{equation}
\ \require {cancel} E_r = 0 \ or \ E_i= 0 \ \wedge \ \cancel {E_r \otimes E_i=0 } \
\end{equation}

Circular polarization
\begin{equation}
\ \mid E_r\mid =\mid E_i\mid \ \wedge \ \cancel { E_r\otimes E_i=1 } \
\end{equation}

Elliptical polarization
\begin{equation}
\  None \  of \   the\   conditions\   above
\end{equation}

Edited with correct answer given by simplicis veritatis, and a own example since thus I can remember it even better.

Lineal polarization

\begin{equation}
\ E_r = 0 \ or \ E_i= 0 \ \wedge \ E_r\centerdot E_i\neq0 \
\end{equation}

Circular polarization
\begin{equation}
\ \mid E_r\mid =\mid E_i\mid \ \wedge \ E_r\centerdot E_i=0 \
\end{equation}

Elliptical polarization
\begin{equation}
\  None \  of \   the\   conditions\   above
\end{equation}

Example
\begin{equation}
\ E = (\hat{x}+\hat{y}-j\hat{y} ) *exp(j* \varphi)\\
\ E_o = \hat{x}+\hat{y} +j*-\hat{y} = E_r +j*E_i\\
\ \mid E_r\mid = \sqrt{2} \\
\ \mid E_i\mid = 1 \\
\ \mid E_i\mid \neq \mid E_r\mid \\
\ E_r\centerdot E_i =1-j \neq 0 \Rightarrow Elliptical Polarization
\end{equation}

Thanks in advance


texts: As the picture shows I have a via fence with one of the vias solder layer touching a trace. Will this short the trace or do I only need to worry about the via hole as there is no soldering on that mask.


texts: Analog amplifier analysis using Hybrid-π transistor model

texts:
I've been told the gain of transistor Q2 is gm×RC2. That is the formula for a common base biased transistor without a resistor at the emitter affecting the gain.

If RE2 was affecting the gain of Q2 its gain would be: gm×RC2/(1+gm×RE2), but it's not.

My question: Why does resistor RE2 not act to degenerate the AC voltage gain of Q2?

Picture of circuit:


texts:
I am a total novice but not unintelligent. I want to use a single solar panel to switch on some lights when it gets dark and also charge the batteries for the lights.  I have previously successfully done this using a JFET, but have to have TWO solar panels, one to switch off the JFET and one to charge the batteries. I have read on numerous web sites that I can use a PNP transistor.  As far as I can understand it they ALL say that a PNP is ON except when a base current is applied.  Example circuits are shown.  I have bought quite a few PNPs, different values. I have tried all of them in the suggested circuits.  I have tried all of them with just a battery and a bulb.  None of my PNPs are on with no base current, they all only switch on when I apply a current to the base.  This is the opposite of what all these sites are saying.  What am I not understanding?  Connect battery +ve to PNP emitter, connect pnp collector to +ve of LED, connect -ve LED to -ve battery NO light.
Connect -v of solar to pnp collector and  +ve of solar to pnp base and LIGHT.  This is the exact opposite of what I want.  What am I doing wrong


texts: High-speed computer interface with an Arduino

texts:
I'm planning a project with an Arduino that involves handling a lot of requests from a host computer, and the standard 115200 maximum baud over serial isn't sufficient. I'd like to be able to get 1Mbps full duplex if possible, but 400Kbps+ full duplex would be acceptable. I'm using an Arduino Due, so it should be able to handle significantly higher communications speeds.

Is there a way to significantly increase the baud rate over serial, or is there a second option I can go for in terms of interfacing with a computer at higher speeds?


texts: Cheapest iButton (1-wire) adaptor/programmer scheme

texts:
I want to be able to read and write and program iButton (1-wire) devices mainly DS1990A and EPROMs. The problem is that any driver chips and readers and adapters by maxim are expensive here.

Is there any other cheaper DIY solution to connect iButton to computer using any usual interfaces (usb, serial, parallel, etc)?


texts: ESP8266 line voltage detection, schmitt trigger needed?

texts:
I want to read 230V/50Hz line voltage input signals with an ESP8266.
Please have a look at my schematic, I chose an opto-isolator with AC input (LTV-354T) and added a simple RC filter to keep the digital input at low level during the zero crossing:

I simulated the filter with LT spice and noticed that the output signal has a long rise time (approximately 10ms):

My question: Should I add a schmitt trigger/buffer?

The ESP's datasheet doesn't reveal much about its input stage, maybe the chip already has schmitt inputs?

Another (additional) question, I hope this is allowed: What is the lowest input/LED current you would recommend?

The current circuit drives the opto isolator's LED with 1,6mA. I'd like to lower the power consumption and heat dissipated by the resistors.


texts: Hi everyone. Please i am trying to derive the state space representation of the circuit above. Please i need some help or a textbook for better understanding of this.


texts:
The problem statement is not exactly on synthesizing circuit but in one of the interim steps that I am trying to learn.

Problem Statement.

1)   In order to design a sequence detector in Verilog (using structural modeling) I was learning to synthesize digital circuit first and stumbled upon a tutorial which I could relate to my problem as given here:-

2)   Everything was smooth sail until I came across this section on the page numbered 273 (5th page of the document). Attaching the snapshot of the dubious section

.:-

3)  What I could not understand is the 'Match' Row below the truth table.
My initial impression was some sort of reduction from K-map; but either it isin't or my method of doing it wasn't correct.

4)  In all likelihood it may be some other silly thing that I may be totally ignoring, but just to support my point, I have only started to 'make it all work together'

Any help will be highly appreciated.


texts:
I'm looking to drive 12v logic signals (logic level shift) from a PIC24FJ MCU, which can do 3.3v and 5v logic. In one instance, I need to switch a 12v line to LOW, and in an other, I need to provide a pretty constant HIGH 12v. Both of these lines appear to sink a couple mA at most.

Would a relay be my best option for driving these lines? If so, are there any small SMD relays suitable for the job?

Response should be within milliseconds and they do not necessarily need to be low power consumption.


texts:
I'm trying to simulate crowbar circuits, which is mentioned on page 8 of ON SEMI TL431 datasheet (https://www.onsemi.com/pub/Collateral/TL431-D.PDF). I'm using TINA TI for this.
There are two circuits, one with TRIAC, another with SCR. Trip voltage formula for both is the same, Vtrip = Vref*(1+R1/R2). However, simulation of TRIAC circuit shows that it trips at about 10.8 V instead of planned 15.25V:

If I change internal resistance of VS1 from 0 to 50 mOhm, simulation renders out expected result. Also, adding reverse polarity protection P-MOSFET makes crowbar to trigger at any input voltage:

Circuit with SCR demonstrates expected simulation results both with and without P-MOSFET:

20 Ohm resistor in each case is imitating a load. In real application load will be some complicated device with about 500 mA consumption.

Questions are:

Why TRIAC circuit simulation shows such results?
In SCR circuit did I chose R5 and R6 values (1k both) correctly?


texts: s25fs256s serial flash not responding with RTD2660

texts:
Hello guys,,
             I am interfacing RTD2660 with s25fs256s serial flash using SPI. but when i send the command_type(0x46 (comman instruction type is read)) and command_data(0x9f (command for Device ID)) to RTD2660 to communicate with serial flash and read the Jedec ID but always it returns only 0xFFFFFF
at 0x67(high byte),0x68(middle byte),0x69(low byte) - >
0xff,0xff,0xff
 .
please help me out.


texts: Ferrite ring vs ferrite choke interchangeable?

texts:
I am assembling a Gimbal controller that needs "Ferrite rings".  Can I use Ferrite clamps instead?  Do they do the same thing?

manual requirement:

What I want to buy:


texts: Tracking movement of limbs for smartphone app

texts:
I'm looking at building a smartphone app that will need to track the users limbs (say legs/feet) as accurately as possible. The goal is to trace the moments of body parts and the timing of the movements in relation to each other.

I'm more of a computer science guy than an electrical engineering guy and am not quite sure how to do it. How realistic it is.

There seems to be a similar question here: Sensor for hand/foot location in relation to a persons body

Is seems to make senses as far as distance is concerned but I need direction as well.

I was think accelerometers might be worth looking at but how accurate are they and do they need to be calibrated often? For example if the accelerometers were on a persons feet would they have to stand with their feet together to calibrate and then you would be able to work out new locations based on their movements from the calibrated position?

Bluetooth proximity sensors seem to only tell distance and not direction and don't look to be accurate enough.

Any ideas?


texts: I want to put some solar cells on the roof of my van to powerup some stuff while the van is off. I would like to know how much area of blue solar cells (they look like cracked blue glass) I need to generate 12V 30-40amps in clear sky at noon?


texts: Determining Impedances of an Op-Amp Circuit

texts:
I'm trying to review some old concepts, and thus far, there was one that I couldn't really understand: impedance of circuits involving op-amps. Assuming an ideal op-amp, it has infinite input impedance and no output impedance, but that's only for the op-amp itself. I'm having trouble understanding how to find the input/output impedance of some op-amp circuits as a whole.

Take the standard non-inverting amplifier for instance:

simulate this circuit – Schematic created using CircuitLab

Using the ideal op-amp rules, since the non-inverting input is connected to the input voltage through Z1, the input impedance would be infinite as no current can flow through the op-amp terminals. However, when you look at the output impedance, you remove the input source by shorting it to ground, making the non-inverting input equal to ground (as well as the inverting input). My book says that the output impedance would be 0, but I don't understand how this is the case. Replacing the load resistor with a current source, you just see an internal op-amp 'output' resistance of 0 ohms in parallel with Z2 to ground, so is that set of parallel impedances the cause of the 0 ohm output impedance? Is this logic correct?

It feels that because of the nature of the ideal op-amp having 0 output resistance, all op-amp circuits would have 0 output resistance. Is this always the case, or are there some exceptions? I'm trying to develop some methodologies for measuring such impedances in circuit problems as it's hard for me to wrap my head around.


texts: Need help finding flaw in the voltage regulator circuit

texts:
I made a discrete voltage regulator circuit and constructed it. There input comes from a bridge rectifier fed by a 15V 10A transformer.
The output current is limited to 3.3 Amperes. Why is that, how can it be corrected?


texts: Post build flashing of configuration data in embedded systems

texts:
I need to implement a mechanism by which I should be able to update the configuration data of some of the modules in a post-build fashion. To describe, consider I have the following files:
 Module.c, Module.h, Module_Cfg.c and Module_cfg.h.

All of these are built together and flashed initially. But at a later point, I want to modify only the Cfg.c and Cfg.h and flash them separately (in a dedicated configuration memory area) without flashing the actual application from module.c. I already tried something like creating a separate project just to compile the Cfg files, but it doesn't work because the main() function etc. is missing. What is the best method to achieve this?

The project is in the automotive area, which has the AUTOSAR standard already defining mechanisms to do this, but it is heavily tool dependent and not easy to understand. I am looking forward to a simple and straight forward solution.


texts:
I have a fixed set of 9 values that needs to be sorted in an FPGA.

What would be an optimal sorting algorithm to implement?


texts: Pulse-width modulation: how to set the duty cycle using two variable sources?

texts:
For a hobby project, I am trying to build an electrical circuit in which the brightness of two LEDs can be determined using two sensors: one for light (an LDR), and one for sound (a microphone, electret is preferred). After the construction of the circuit, I would like to still be able to change the maximum brightness of the LED, as well as how much the brightness is determined by light or sound. In the supplied image, the characteristics of the system are shown.

The least trivial questions for building this circuit is how to combine the two "inputs" (sound and light) to determine a duty cycle, as well as how to set the percentage of influence of both sources. Given the following:

max = the maximum duty cycle sent to the LEDs
l = the amount of light observed
s = the amount of sound observed
p = the percentage of influence of light on the total duty cycle

I would like to know which circuit would satisfy the following conditions:

$$\text{Duty Cycle} = \text{max}( (p(1−l)+(1−p)s )$$

Furthermore, the power source should be as small as possible (e.g. 2 AA batteries) and be able to last for 50 hours.


texts: How do you remove the buzzer from this PCB whose solder side is inaccessible?

texts:
(Click on an image to see in original size.)

There is this buzzer in this UPS (uninterruptible power source) circuit. I want to remove it from this circuit because it make a lot of unnecessary noisy. Black-outs happen too much in my area. Sometimes they happen in the deep night, when I am sleeping, and this little buzzer wakes me up by freaking me up. I always immediately realize it when there is a black-out, so this buzzer is really not needed.

I am not able to de-solder it. Because the PCB is strongly embedded into the case by some very hard clippers. It just won't move.

How do I remove this buzzer from the circuit, or shut it up without removing? I don't plan to re-use it, so it is OK if it is destroyed in the process. I just don't want to get into risk of damaging any other part of the PCB.


texts:
I've already done the datapath for my system using a synchronous reset and now I have to control everything using state machines. What I'm confused about right now is whether or not the reset signal should be tied to a separate state which then sends a reset signal to all the processes or have the reset signal tied to the control and data-path processes.

I'm not under any timing, space or speed constraints but I would like to know if one method is always better than the other or if certain conditions apply. Any advice or direction would be appreciated.

EDIT: I've looked at this whitepaper on the topic of resets but I'm still not sure.


texts: Does manufacturing different sized hard drives cost the same amount?

texts:
Is there a major difference in the cost of manufacturing, say for example, a 1 TB hard drive as compared to a 250 GB hard drive? Is it the same when hard drives get even as big as 8 TB?

If no, then why is the price difference so great between the two products? ($17 vs. $77 for 2.5 inch Hard Drives on Amazon)

If yes, what is the reason it cost more money to fit more space on a hard disk? How does disk capacity work, and how do technology companies eventually make even larger hard disks?

Also, is it the same situation for flash storage, solid state drives, and SD cards?

I figured Electrical Engineering was the best place to ask this instead of Stack Overflow or Server Fault, as it was more hardware-related and I hope it isn't too broad or general. If this is the wrong place, any guidance as to where the best place for this question is would be appreciated. Thanks.


texts: Lockup when executing relocated ISR in ARM Cortex-M0+

texts:
I've been writing a small program for my Freescale Kinetis KE04Z which runs in RAM in order to program the flash of the device. I've been using SWD to place the program in RAM and run it. All was going well (blinking LEDs as a test, etc) until I tried to start the periodic interrupt timer (PIT module) in order to confirm the speed of the microcontroller by flashing an LED with some specific timing (the flash controller manual says that if the speed is wrong then it could destroy the flash). I don't have an oscilloscope available at the moment, otherwise I would just ditch the PIT, write the gpio pin toggle register (PTOR) over and over again, and measure the period of the resulting square wave.

I have in my startup section the following assembly which moves the VTOR to my interrupt vector table:

ldr r0, =0xE000ED08
ldr r1, =__interrupt_vector_table
str r1,[r0]

__interrupt_vector_table points to the beginning of the RAM section where I have placed my interrupt vector table (0x1fffff00 for the record). The code can be found here. The interrupt table and startup code listing is here.

In my main method I have the following:

SIM->SCGC |= SIM_SCGC_PIT_MASK; //turn on PIT clock
PIT->MCR = 0; //activate PIT
PIT->CHANNEL[0].LDVAL = 1.2e6; //100mS tick
PIT->CHANNEL[0].TCTRL = PIT_TCTRL_TEN_MASK; //enable the timer
PIT->CHANNEL[0].TCTRL |= PIT_TCTRL_TIE_MASK; //enable the interrupt
NVIC->ISER[0] = 1 << 22; //enable interrupt in NVIC
__enable_irq(); //cpsie i

It was at this point where I started to run into problems. Once the PIT would go off, a lockup would occur according to the SIM_SRSID register when I read it via SWD. I have a couple thoughts on why this could happen:

The ISR runs, but never returns, causing the WDT to go off an initiate a reset, causing the VTOR to be reset to 0x0. Since the device is unprogrammed, the reset vector is 0xffffffff, which causes a lockup.
The ISR runs, smashes the registers, and prevents the main method from properly resetting the WDT, causing the same situation as above.
The interrupt goes off, but for some reason the NVIC is unable to run my ISR and initiates a HardFault. My hard fault code just loops forever, which would eventually cause the WDT to go off and etc.
My hand-written interrupt table is off-by-one and one of the default ISRs is getting executing and causing a WDT timeout (or I'm not enabling the correct ISR and the same thing is happening). The thing is, I've never been able to show that my default ISR code was running instead of my actual IRQ handler. I've done a few tests using writing memory locations to specific values and then reading them after the reset and the code to set those values has never executed.

I'm pretty sure it has to do with my ISR or the interrupt in general because once I comment out the line of code that sets PIT_TCTRL0.TIE the program works fine and doesn't lock up.

My ISR is really simple right now:

void PIT_CH0_IRQHandler(void)
{
    PIT->CHANNEL[0].TFLG = 0x1; //reset flags
}

Which compiles to:

2000001c <PIT_CH0_IRQHandler>:
2000001c: 2201       movs r2, #1
2000001e: 4b01       ldr r3, [pc, #4] ; (20000024 <PIT_CH0_IRQHandler+0x8>)
20000020: 611a       str r2, [r3, #16]
20000022: 4770       bx lr
20000024: 400370fc strdmi r7, [r3], -ip

I honestly don't know if this is right. There is no context saving going on or anything else that I've seen in other ISRs, but I've never looked in detail at ARM Cortext M0+ ISRs so for all I know the NVIC takes care of context saving.

My question is:

Is my ISR code, NVIC code, or VTOR relocating code the problem here?
Or perhaps is locating the VTOR to a location in RAM a bad thing and won't work properly?

This is my first time writing a program that runs in RAM and also my first time relocating the VTOR, so I don't have a lot of experience in these matters. I've done lots of interrupt code for a K20 before, but the VTOR was always at 0x0. If I've left anything out or need to supply additional information, just let me know.


texts:
I have written testbench in verilog. All the test cases define in task works independently well but when I try to run both task then it give proper output for 1st task in task_operation but not for other task. The stimulus remain there for another task also. I want to use input in task as locally instead of globally define. How should I define input in argument in task so that input should be given independently?

module tb();
  reg data_i_t;
  reg dcsel_t;
  reg clk ;
  reg reset_t;
  reg reset;
  reg read_t;
  reg xlat_t;

  initial begin
#2 reset =0;
task_operation();
#100000 $finish;
  end

  task task_operation();

    begin
      exp_case_2a(data_i_t,reset_t,read_t,dcsel_t,xlat_t,data_out_1);
  exp_case_2b(data_i_t,reset_t,read_t,dcsel_t,xlat_t,data_out_1);
    end
  endtask

  task exp_case_2a;
    input data_i;
    input reset;
    input read;
    input dcsel;
    input xlat;
    output reg [47:0] data_o;
    begin
      repeat(47) begin @(posedge clk)
    data_i = 1;
    reset   = 0;
    read = 1;
    dcsel = 0;
    xlat = 1;
    data_o = Data_out;
      end
      #5250  compare_data_2(data_out_tb);
    end
  endtask

  task exp_case_2b
    input data_i;
    input reset;
    input read;
    input dcsel;
    input xlat;
    output reg [47:0] data_o;
    begin
      repeat(47)begin @(posedge clk)
        data_i = 1;
        reset  = 0;
        read   = 0;
        dcsel  = 0;
        xlat   = 1;
        data_o = Data_out;
      end
      #5250 compare_data_2(data_out_tb);
    end
  endtask

/* ...........  SCORE-BOARD..............
   task compare_data_2;
      input [47:0] exp_data;

  begin
 if(exp_data == `comp_data_1 )
   begin
       `INFO("TEST PASSSED",$time);
      $display(" exp_data  : %h ",exp_data);
   end
 else
   begin
       `ERROR("TEST FAILED",$time);
      $display(" exp_data : %h ",exp_data);
   end
  end

endtask


texts: recieve ACK after sending address in I2C in EFR32FG14

texts:
Hello in I2C we send data to the slave using I2C->TXDATA register.
on the same line we need to recieve ACK response from the slave.
From SPI expirience i know that for the slave to respond master  needs to send the slave it dummy bits to provide it with clk.
But the ACK is only one bit,how  do i provide a clock of 1 bit?
Thanks.


texts:
To begin with, I must say this is kind of a "homework" but I tried to do it on my own and I haven't succeed maybe someone can help me out with this matter.
We're learning about digital systems, circuits and so on. Therefore, our next laboratoy is going to be about Monostable and Astable circuits (Using the timer 555). Being proactive I decided to have a look to the topic before having the class so I would understand better, the video showed the following circuit (which is a Monostable):

It was made in the software Circuit Wizard and I understood what are their differences and how those circuit work. However, when I tried to do it by myself I couldn't. The only little difference is that I used Circuit Maker and the elements seem to be different from the others used in the video. Here's what I got:

I hope you can see the unseen to make it work. I keep getting a message which says "the selected elements may not work in this simulation mode", is there a special "simulation mode" for this circuit? Thanks in advance.


texts:
I am trying to connect many (~80) ToF distance sensors VL53L0X onto a single i2c bus. They have the default i2c address 0x52, which is programmable, but not persistent. Thus I have a choice between selective turn on/off of sensors (via GPIO expansion on i2c etc) and reprogram each individual address at startup, or have the addresses translated on-the-fly in hardware. This is about the second option.

There would be the translator T (something like LTC4316, but preferably one without voltage dividers) always between the sensor S and the bus, like this, each translator set for a different address, of course:

master ---+---+---+---+
          T   T   T   T
          S   S   S   S

Now I would like to be able to connect another identical modules like this one after another, but to prevent address clashes, each module would have a translator N at the beginning:

(--  module 1 --)     (--  module 2 --)      (--  module 3 --)

M---+---+---+---+ === M---+---+---+---+  === M---+---+---+---+
    T   T   T   T         T   T   T   T         T   T   T   T
    S   S   S   S         S   S   S   S         S   S   S   S

Module 1 would be translated by M, module 2 by MM, module 3 by MMM and so on, for example like this (with sensor address 0 for simplicity, T adding 1, M adding 4)

global address        4  5  6  7     8  9 10 11   12 13 14 15
module-level address  0  1  2  3     0  1  2  3    0  1  2  3
sensor address        0  0  0  0     0  0  0  0    0  0  0  0

I would like to have a comment whether this is a good way forward logically, whether it makes sense electrically and perhaps even a suggestion for IC similar to the LTC4316, with translation address selectable by pulling pins high/low.


texts: Connecting two USB *clients* together (SiK radio problem)

texts:
I need to connect a typical USB SiK radio to a USB client.

The other radio is plugged into a PC so is not a problem. But I don't have a Host device for the other end, and while I can provide +5 power, obviously I need something (ideally a single chip or very small solution) to act as a Host, so that the radio can communicate with the USB client device.

I suppose an Arduino could be programmed for this but I'm looking for a way to solve this more elegantly.


texts:
I have an analog circuit that outputs voltage between 0-5V. A simple representative circuit is given below.

The ADC can tolerate up to 4V and the interesting signal that I like to digitize is between 0-3.3V. In other words, it is ok to read all 1's at the ADC if the signal is more than 3.3V?

I am trying to find a circuit where it doesn't introduce:

Additional noise
Doesn't disturb my signal if it is not above 4V
fast enough to deal with my 1 MHz input signal (zeners are out at least I couldn't find one that is fast enough and small noise)

Any help would be appreciated.


texts: Why use convolution for pulse compression in radar instead of correlation?

texts:
I have not understood the way to process pulse compression in radar signal processing. I think it's correct to use correlation for pulse compression, but I saw many materials about pulse compression. Then, they use convolution.

These drawings are my thinking. When I use correlation in first drawing. The output signal has max power. Because Transmit Signal is similar to Receive Signal. But when I use convolution, receive signal reverses. So I think this output signal power is smaller than output signal's power of first picture.

Using Correlation:

Using Convolution:

Why use convolution for pulse compression? Please help me. I want to get intuitive description.


texts:
I was looking at some classic logic IC:s like the 74-series and could not help to wonder when they where designed, since it feels like they have been around a very long time.

If we take a example, how old is the 74HC595 design?


texts:
Could someone explain me why is the response so in the yellow marked area?
Since in the rising edge of the clock we hve J=0, K=1 the output in the falling edge shouldn't be Q=0?

It is a master slave flipflop


texts: A circuit to convert 4-bit Gray numbers to BCD

texts:
I'm sorry for asking this specific question here but can some one please tell me what's wrong with this solution.

Question: design a circuit to convert 4bit Gray numbers to BCD

I have to say I wrote numbers in Gray form in the left hand side of the truth table.

Let's consider a number such 1000 in Gray

My solution:

It's binary equivalent is 1111 and we cannot show that in BCD so output have to be don't care

Here is what my professor says:

Binary equivalent: 1111

Decimal equivalent: 15

BCD equivalent:00010101

I'm completely confused :|

Edit:

As some users noted I wrote grey codes in non sequential order.

But the answer of karnaugh map will remain same. To see this you can compare the link @Jack Creasey added as comment and my karnaugh maps.(also note I just designed this circuit with decoder)


texts: Connecting multiple encoders in to STM32 TIMx hardware counter (using channels 3+4)

texts:
I have a requirement to connect 3+ standard rotary encoders (A/B quadrature) into an STM32 - the STM32L072x is the current choice.
While I could bit-bang it, it would be nice if I can just use the standard STM32 TIMx hardware General Purpose Timer (GPT) counters in encoder mode.
However, the datasheet / programming manual is very vague on anything other than a single encoder connected to TI1/TI2 channels of a timer (EG Timer 2 Channels 1 + 2), the CubeMX software appears to let me hang a 2nd encoder from (for example) Timer 2 Channels 3+4.
This would mean I can (for example) connect;
Encoder 1 --> GPTimer 2 CH1+2
Encoder 2 --> GPTimer 2 CH3+4
Encoder 3 --> GPTimer 3 CH1+2
etc...
Is this correct? Has anyone successfully done it?
EDIT: Accepted the correct answer (which is "no you can't"), however it looks like CubeMX actually multiplexed pins, so T2C3/T2C4 are shared with T21C1/T21C2 on the same pins and it was in fact using T21 for the 2nd encoder input.


texts: Microcontroller + DC motors oscillation problem

texts:
I have designed a simple circuit for using AVR microcontroller (Atmega328) for controlling few DC motors.

Everyting works perfectly with just one motor connected - but after connecting the second one, circuit gets into strange kind of oscillation (around 15 Hz) of turning on and off. I am pretty sure I have enough current from power supply (500 mA), the motors are very small (cellphone vibrators).

Any ideas?


texts: What's the purpose of crossing over in the middle of a toroid winding?

texts:
Seeing toroids wound like this is somewhat common in the amateur radio hobby to reduce common-mode current on an antenna feedline:

Why the cross over the middle? As far as I can tell, all the turns go around the core in the same direction. Why not just keep winding all the way around?

Sometimes they are also seen with two enameled wires instead of coax:

Is this any different? As far as I can tell, it's effectively a common-mode choke in both cases. Does the cross over in the middle serve any purpose?


texts:
I have a simple circuit which contains an MSP430 connected to a DAC8551. I'm using PORT1 so have implemented a bit-banging approach instead of using the USCI module (bad, I know).

I've noticed a strange phenomenon with my logic analyser. In steady state operation, I observe whatever value I'm sending to the DAC as expected. When I switch the power off, I sometimes get another value, in particular I get 4784 (0x12B0).

Once I switch off the supply I expect Vcc to drop from 3.3V to below the minimum 1.8V after some period of time, potentially causing a BOR and then to shut-off completely. I can't explain why I would consistantly observe '4784' on pin 1.1 in the last transmission before Vcc goes to 0. The relevant code in my code to transmit to the DAC is below.

for (i=8; i!=0; i--){clkDAC();}
//clk in don't care bits
for (i=16; i!=0; i--){  // Set MSB first
    if(value & 1<<(i-1)){
        P1OUT |= BIT1;
    }
    else{
        P1OUT &= ~BIT1;
    }
    clkDAC();
}

Any help appreciated.

Edit:

I've noticed that I was getting the same problem at the very beginning of my transmission, and I fixed that by adding a delay in my init_clk function, apparently the processor can't go straight into operating at 16 Mhz until Vcc rises past a certain threshold. I believe the same effect was happening when I switched the power off. I'm still interested in why it was always a particular value though.


texts:
I'm facing a strange issue and I can only think of a ground loop but the problem seems excessive. I have a three pcbs, one for some supplies, one main and one optional that can be plugged on the main board. The main and optionnal board are connected together with two mezzanine connectors that are located on opposite sides (see figure), each of them has their fair share of ground pins.

When the optionnal board is not connected, everything goes fine. When it's connected there's a communication bus on the main board that crashes.

Now what really bothers me is that I can't understand why it would cause problems to my bus if it is a ground loop issue.

The bus is controlled in impedance and really short and by short I mean traces of 1.5cm for a rise time of 1ns and a frequency of 100Mhz. Here's a screenshot of a layer with signals from the bus, it's far from perfect but I don't really feel any danger here for SI...

All of the IC's on the optionnal board should be quite inoffensive there's only things like digipots, eeproms, etc. And there's no short circuits.

I haven't seen any problems with the dedicated power supply for the bus.

The only high frequency signals on the board are USB3 signals.

The communication bus starts with some kind of synchronisation on which I don't have any control and I think this is the part that crashes because if I hot plug the board after it is done the bus still works. I can't probe the traces when the optional board is connected.

Am I missing something important here ?


texts:
I have a large potentiometer ( that we also call a variac) that is rated for 220V at input and a 0-250 V 8A ouput.

My mains run at 230 V and 50 Hz at 16A I assume.

Is the difference in current the cause of the heating ? Or is it that I have bad connection with the load ?


texts:
I am using a regulator in a design.  The regulator gives 5V output with 9V to 60V input.
The datasheet says that the input transient voltage is 80V/second.
Does this mean the regulator can handle an 80V transient for 1 second?
Data sheet:https://gaia-converter.com/docs/ds/MGDD21W.pdf


texts: Is there a solution for keeping circuits with low frequencies small?

texts:
background
I'm essentially making an mixed-signal/analog computer(to accelerate certain mathematical operations). I'm looking to create many AC filters (of different types) at low frequencies (sub 500Hz) Currents & Voltages are unimportant (I can make the voltage and current really low or really high if necessary)

the problem
The problem I have been running into is that I often need HUGE capacitors(even with low voltage) and inductors(even with low currents) to get the job done. I've used active filters to solve the problem in the past, but the extra components they require usually wind up taking up the same amount of space.

(if possible)
I'd like to stick with through-hole components so I can prototype, but surface mount is fine too. Higher signal integrity is preferable to low signal integrity, but I can make sacrifices.

Any ideas on what I can do to keep things small(cheap is always a plus)?


texts: PWM signal with NMOS to adjust LED Driver

texts:
I have to design an LED driver for work. I am using the IS31LT3360 as the driver chip. On page 10 of its datasheet it states the chip can be driven with pwm. I came up with the following circuit. I would appriciate any feedback on wether I am doing this correctly. The mosfet is driven with a 0-3.3V PWM signal.
I am a little confused about this line on the datasheet:
"The PWM signal must have the driving ability to
drive internal 500kΩ pull-up resistor. "
What does that mean? I am not sure what driving a resistor means.
Datasheet IS31LT3360 :
http://www.issi.com/WW/pdf/31LT3360.pdf

Edit after Marcus's comment. The datasheet suggests using a MCUs output (AS LONG AS IT IS BELOW 5V AND ABOVE 1.2V, better?) as below to drive the chip.


texts: How long will this low duty 555 LED blinker last on batteries?

texts:
I know there are many questions about LED blinkers, but I haven't yet found a clear answer for this.

I have a 555 circuit blinking a blue led (or three in parallel). I has a low duty cycle (using a diode between pins 6 and 7).

simulate this circuit – Schematic created using CircuitLab

It works fine (blinks the LED without resistor, giving a very bright light) when powered off a USB 5V source, but I have no clue as to what the power consumption is.

I want to transfer this design so it can run on batteries for many hours as a beacon (at least for weeks) (I will add a magnetic switch so it can be waterproof). I need it to last as many hours as possible, without much bulk. Is this circuit moderately efficient for that purpose?

Clarification : It will be used as a beacon, off for 1-1.5 seconds, then on for a very short time. No accurate timing required. It is working as described now with the only difference being that the 20k resistor is in fact a 10k plus a 10k pot to play with the timing while prototyping.


texts:
I am looking for guidance on audio functionality test over USB audio codec. This audio output serves as Alarm to indicate certain events.

The signal flow is ARM processor USB port --> USB Codec --> Class D amplifier --> 4 ohms speaker

For diagnosis purpose, I want to detect the presence of analog output from the amplifier and convert this into digital signal (high or low transition), so that the processor would know whether the analog audio section is OK or not.

The signal flow is Class D amplifier --> Audio sense circuit --> Processor GPIO.

Please help me with ideas on how to implement such a feedback circuit.


texts:
I need to receive a 24V signal from an automated industrial system. The receiving board is a UDOO system that its I/Os can handle voltages until 3.3V.

Any ideas on how can I make things work?


texts: Amplifier speaker outputs: is the black always the chassis?

texts:
Any amplifier or A/V receiver that I have seen has a black and a red terminal for each speaker.  From 2 pairs for a simple stereo system up to 7 or more for an A/V receiver.

It is quite a while since I have looked inside an amplifier but, for at least some, the blacks are common and connected to the chassis.  Can I safely assume this or are there any common or likely amplifier designs in which the black terminals might not all be at the same potential?

Edit: Chassis might not have been the best word; as people seem to have picked up, the significance is whether they are all necessarily at the same potential.  My outlook is still biased by early experience with valve devices: radios, TVs, amplifiers, in which a metal chassis (not an external casing) was usually a common 0V reference.


texts: Eagle UI: separating hundreds of components that are stacked on top of each other

texts:
I finished a complicated schematic in the free version of Eagle, switched over to the board editor and was encountered by this:

In case the image doesn't say it all, there are about 100 components all stacked on top of each other with the same origin.

Separating them manually will take ages, is there a way I can fix this automatically so I can place my components?


texts: Can I hook this breakout board up to the thing I want to measure?

texts:
I have a piece of tech that uses somewhere between 50-200mA, and I want to continuously measure the current used. To this end I have found this:

Sparkfun ACS712 breakout board

Allegro ACS712 chip datasheet

I've hooked up the supply voltage to an arduino 5V and the GND to the corresponding GND on the arduino. The reason I've chosen to use my Arduino for the supply is that it gives a stable 5V all the time. I've connected both of the IP+ channels to each other and the two IP- channels together aswell. After this i connected it to my unit like this:

[12V PWR 1A]+ --> [[IP+]CIRCUIT[IP-]] --> [+[The piece of hardware I want to measure]-] -->[GND]

I have to set Vref on the board when the thing is disconnected by measuring the voltage over V0 and GND and turning the Vref until it says 0V. But then what? What do i do next?


texts: posedge clk vs posedge clk, posedge reset

texts:
I'm looking for the difference between:
always_ff @(posedge clk) begin

and:
always_ff @(posedge clk, posedge rst) begin

Here's what my slides say about that:

Can someone elaborate the idea, plus why it's not the opposite? I think right should be asynchronous as left checks only when reset goes up while right checks all the time (correct me if I'm wrong)
Another thing: I have seen something like always@ what does that mean?


texts:
I'm working on an isolated 2-sw forward converter.

The output section has a toroidal inductor that I've a problem with. Here's how the output section looks like:

simulate this circuit – Schematic created using CircuitLab

The switching frequency is 100kHz and the required value of the output inductor is calculated as about 100uH.

I put a toroidal 100uH inductor (I think it has iron powder core) taken from a broken power supply and left the converter operating under 6A load for half an hour. Then I measured the output inductor's temperature as 50°C which is quite acceptable. So I calculated its \$A_L\$ (from \$L = A_L \cdot N^2\$ of course) as about 95nH.

Then I bought an iron powder core (Part Nr: T130-26K - http://www.pe-coils.com/IPC.htm) having the same dimensions as the other one and calculated its \$A_L\$. Surprisingly, it has the same \$A_L\$ value! I thought that I "accidentally" found the same core, so I wound a toroidal inductor with the same number of turns and using the same dia wire. As expected, I got a 100uH toroidal inductor. No problem until here.

The problem is this: If I use my hand-wound inductor, and under full load, it gets as hot as 95°C! How can it be? They both have the same wire thickness, the same inductance and cores with the same \$A_L\$ values. But where does that temperature performance comes from?

More funniness: if I use my hand-wound inductor, I get %87 efficiency; but if I use the other one, I get %92!

I measured Q values of both with a calibrated LCR meter: My hand-wound has 2.4 but the other one has 1.8. So, what can be the thing behind this issue? What should I do?

[SOLVED] EDIT:

I've experienced that it really comes from core losses. The one with model number of T130-26K is a quite lossy one. So I purchased some toroidal inductors from Mouser and tested each under the same conditions. Finally, one beat them all in terms of thermal and electrical performance. For the ones who are interested, it is 2300LL-101-V-RC from Bourns.

PS: Is there a way to close or flag this question as "answered" or something like that?


texts:
With Bluetooth Low Energy, you specify a scan window (how long to scan) and interval (how long to wait between scans).

Would there be any difference between scanning for 10 ms every 100 ms, or scanning for 1 sec every 10 sec? Seems like the chance two devices find eachother (have their radios on simultanously) should be equal in that case?

Is there a simple formula to calculate the right window/interval based on the maximum time allowed to connect?


texts: Why the opposite of the passive sign convention is not the active sign convention?

texts:
Studying the fundamentals of circuit theory, I was reading the Wikipedia article on the Passive Sign Convention and found out about the Active Sign Convention (ASC). After searching many introductory circuit theory books - such as Nilsson's and Dorf's ones -,I realized that almost none of them mentions "Active Sign Convention". When some circuit element is with the current entering in the negative terminal, they say something like "the current and voltage reference directions are not in conform to the passive sign convention", as shown in the pictures below:

Images sources: Introduction to Electric Circuits, 9th Edition - James A. Svoboda, Richard C. Dorf

Searching more about the ASC, I have found these lecture notes that states (page 6):

  Also, what's with the "Not Passive Sign Convention"? In general, circuit elements that absorb power (like resistors) are called passive elements, and circuit elements that supply power (to the circuit!) are called active elements. But for some reason, the opposite of the passive sign convention is not called the active sign convention. (Of course, people use
  the term active sign convention, but they are not supposed to. If you want to be an alpha
  geek, find out why and go around correcting them!) Instead, the awkward term "Not
  passive sign convention" is used. Actually, the full blown correct expression is
  "The element does not conform to the passive sign convention." But that's way too long
  to say or write (unless you are being the alpha geek).

So, my question is: Why "the opposite of the passive sign convention is not called the active sign convention"? Why they use "the current and voltage reference directions are not in passive sign convention" instead of "the current and voltage reference directions are in the active sign convention"?


texts: I'm trying to make a 2 bit adder in Logism.  I made a half adder and a full adder chained together. Some equations work, and some don't. I'm using the structure that I see everywhere on how to make an adder. I don't know what's happening.


texts: What would happen in case of power outage during NOR flash erase or programming

texts:
I am using a SPI-connected NOR flash (AT25DF321a) to protect data against loss during power failure.

But how is flash protected against power loss? What would happen if the power turned off during erase or programming? Is it possible to detect such cases programmatically? (checksums and so on)

For example, if an erase was interrupted, are there all "1"s on the beginning of the erased block? On the end? Or is it totally undefined? I have the same question about programming: are bits programmed in some order?


texts: Cutting and joining a LED strip that has no solder pads?

texts:
I ordered and received WS2812B 5050 RGB Individual Addressable LED strip and for the first time I received an LED strip without cutoff points and with no pads. The product images and description do not match what I received and I have begun the return/refund process.

In the mean time, I'm wondering how would you go about cutting and joining these up? I guess scratching through the top surface to reveal the traces beneath? Since they are individually addressable I'm guessing they can be cut off one by one.

Is this just the cheapest possible way to manufacture these kinds of LED strips without having to include those solder pads?


texts: SPI data storage devices: (micro)SD card, DataFlash, or serial EEPROM?

texts:
I am revisiting some of my design habits, and one of them is under serious scrutiny: the go-to SPI-based storage device is (micro)SD cards, for their price-to-capacity ratio and generally higher speeds.

Among the three major types of SPI-based storage devices - (micro)SD card, DataFlash and simpler 25Cxx series SPI EEPROM (and also put built-in EEPROM on microcontrollers and 24Cxx I2C EEPROM into consideration) which is the appropriate medium for the given use cases below? Bear in mind that I use all medium as raw block devices, so the "SD cards need a filesystem" argument does not stand.

Use cases:

System configuration and calibration data. Examples: MAC address for the Ethernet interface, measured voltage of onboard voltage reference.
Logs. Example: captured data from sensors.
Code and code resources (too big to fit in the program memory or have to be carried portably.) Example: system updates, internationalization and localization strings, user interface resources, fonts.
Security and digital rights management. Example: cryptographic keys (public and/or private, symmetric and/or asymmetric,) digital signatures.


texts:
Hello I have had zero luck with finding anything related to this problem. Lets take the most basic circuitry: switch that turns on the light

The values on the sketch are not accurate, couldn't change the values

How can I "replace" the Switch with Arduino? Do I need Zener Diode to achieve that?

I want to use it to light up a 225V, 330Watts Lamp (I'm in Europe) that is used in my room.


texts: Would these two transistors have the same Beta?

texts:
If both Q2 and Q1 are 2N3904 BJT transistors, can we assume that they share the same Beta?

Thanks for your help in advance!


texts: How does a capacitor reduce voltage drop in a DC motor start?

texts:
I know that a capacitor stores charge:
C=Q/V

but what i don't understand is how this would reduce the voltage drop caused by high current draw.

My theory is that  the capacitor would need to be in parallel with a conductor (minimal resistance) and then connected to the motor.

simulate this circuit – Schematic created using CircuitLab

(Diode is motor)

By doing this, current will only be drawn from the capacitor when the power source can't supply enough.

If this is true why? and if it this isn't true how is capacitor supposed to be set up then? what would happen if the capacitor is in series?


texts: What kind of connector is populated on this PCB?

texts: I've been looking for some sort of leaf spring contact but haven't come across this double-sided variety. Does this look like a COTS connector, or is it just a custom formed piece of copper?


texts: number of independent energy-storage elements in this circuit?

texts:
So I practiced various examples of modeling electrical cricuits and mehanical circuits. I stumbled upon this one:

and it's same as this:

now with these direct substitutions: $$k=\frac{1}{L},\;B=\frac{1}{R},\;J=C,\;T_{(t)}=i_{g(t)}$$
I get these equations:
$$i_g=i_{l1}+i_{l2}$$
$$i_{R2}=i_{l2}$$
$$i_c=(i_{R2}+i_{l1})-i_{R1}$$
I get this circuit:

Now, which number of independent energy-storage elements is in this circuit? Which order is differential equation which describes this circuit and how it looks like? I got this:
$$i_{g(t)}=i c+i_{R1}=C \cdot \frac{d uc}{d t}+i_{R1}=C \cdot \frac{d u_c}{d t}+\frac{uc}{R{1}}$$
Is this differential equation which describes this circuit?


texts: Can I use LT5400 as a single resistor? Can I connect the 4 resistor in series?

texts:
Can I use the LT5400 as a resistor?

I would like to connect series the resistor for example LT5400-1 to receive 10k - 20k - 30k - 40k in series?


texts: number of bits of information for n stable states?

texts:
my text book says

"An element with N stable states conveys log2N bits of information"

i don't understand it since i expect if we have n stable states we would have n/2 bits
since one of them is the bit it self and the other one is it's complement .

why the textbook takes lg of n ?

PS. i think flip flop is the closest tag (in existing tags) for my question


texts: What is the main difference between RST (0-7) and RST (5.5-7.5) in microprocessor 8085?

texts:
What's the main different between these two restart instructions?  On the first case they are 1 byte call instruction and next case, they are vectored interrupts but definitely they are also call instructions. Then why RST (0-7) can't be used as interrupts?  What's the underlying difference between them?

I think I am not able to build the concept of RST instructions and that's why asking this silly questions. Thank you so much for helping me.


texts:
I'm trying to make a cheap DIY LED nigtstand Lamp.

I'm looking for recommendation on which kind of LED I should use to make enough Light to call it a "lamp".

Ideally I would use a 9V battery to power the system. since the whole thing is for a workshop with multiple kids doing multiple lamps.

I've look around on digikey and doesn't seem to find any SMD or TH LED that will do the trick for me.

I bought a few of these.

But the soldering is too hard for kids, and with the small test I made the light emittion seems really low.

Any Idea on what I could use?

Thank you.


texts: Can a higer-voltage switch be used in my circuit?

texts:
I'm playing around with my first circuit assembly on a project I'm working on.

It very basic, just three AAA batteries (4.5v) and several LEDs.
Everything is working perfectly in a simple, direct circuit.

I'd like to put a momentary switch in the circuit so that the LEDs only light while the switch is pressed. I've been googling, and haven't given up yet looking, but it seems many of the switches I'm finding are listed as 100v or 250v.

Can I use a higher voltage-rated switch in a mere 4.5v circuit? Or would they provide too much resistance and prevent it from working?


texts: How to get the IC numbers of the logisim items

texts:
Logisim makes it very easy for user to intuitively manipulate and edit the components already provided to achieve the circuit he wants. But there is no information about the actual IC numbers of those components which is present in Proteus. I could just do a google search, but there are multiple implementations for the same component and thus different IC numbers.

  Is there any way I could find out the IC numbers of logisim components?

EDIT Just to clarify, I'm looking for a way find out the IC numbers of the components. For example, what is the IC number of ROM used in Losigim? I can change the data and address width arbitrarily and that will change the actual IC I can use in the real world. How can I get the number of that IC?


texts: How much resistor does an LED lamp need?

texts:
I want to make a lamp with LEDs, those have to be powered from a socket (230V). I have a cord with a switch and two wires (ground, voltage), which supports up to 1300 W. The switch for turning it on/off.
I want to use this cable with switch and the socket to power 3-6 LEDs (I think serial,) but what kind of resistors do I need, if this all is possible?
(I'm kind of new to this) I read that LEDs have "voltage drop" and "thus changing the amount of current running through it" so V= IR doesn't apply.
With LEDs, I refer to Leds

Is this somehow a good idea (safe, doesn't catch fire, etc.)
What kind of resistors do I need
Taking a 9V battery how do I calculate the voltage drop and the resistance needed?


texts: how to handle a data set with negative values in verilog?

texts:
Suppose I have the following data set

FFDD
FFF5
0006
0007
0007
FFFE
FFFD

So far what I have studied is that verilog stored data in twos complement form, if i take the example of first sample FFDD verilog will stored it as 11111111........ and after the data is processed by my verilog code. it returns me a very huge value which is not desirable.
if I have the following module what modification i have to made so that i can get the proper result

 module asf (in,out,clk,rst,en);
    input [15:0] in; // the input will be data set
    input clk,rst,en;

    output wire [15:0] out;// output of the module
    wire [15:0] h1o,h2o,inh1,inh2,inh3;// output of another module which //can be used as input in this module
.
.
.
.


texts: I am designing a WiFi enabled DALI control device. I have some control gears which already have short addresses, are connected on DALI lines. I want to scan the control gears and store their short addresses in my cell phone app. We have developed a cell phone app which can do so. What should be the commands or queries that i should use to do so? I tried to send query short address command, but it does not work because the gear is not physically selected. What is the best suitable method to do this?


texts:
I am using M95 GSM Modem for remote data communication with the server. The server-end persons want me to use HTTP data connection.

Another embedded guy has suggested to use sockets and TCP data for communication.

I cannot figure out if both of these are same methods or are they fundamentally different ways to communicate remote data using a GSM modem?


texts: Avoiding turn-off of zero-crossing optotriac

texts:
I'm designing a circuit that switches a load using a regular TRIAC (say, a BT-137) being fed by a MOC3063 - an optotriac with zero crossing detection. The circuit being fed by the TRIAC can be either a resistive load or a diode bridge, so there may be no current at the moment the TRIAC turns on. Here's the topology I'm thinking of:

My question is: can I be sure the MOC3063, which has a zero crossing detection circuit, won't turn off? I'm assuming that it can't ever turn off while there is current in the input side, no matter how messed up the load current is - even if it goes below the holding current of the optotriac. Is this a safe assumption?


texts: How do I assemble this LM3914 bar-graph board?

texts:
I bought some of these LM3914 boards from eBay:

The ad said "buyer needs to assemble it" which I was fine with. When I opened it up I saw a board like this:

I have the LM3914 chip (DIP 18) and the LED strip. Now I'm puzzled as to how to solder them both on. It is clear from the photo above that the chip is inserted from below and soldered on top, and the LED is inserted from above and soldered underneath.

Inserting the chip I see this:

If I solder the chip on first, then the body of the chip covers one row of holes for the LED. And if I solder the LED on first I won't be able to solder the chip on, as they overlap like this:

So is there some trick to soldering this together? Or is it impossible without a reflow oven?


texts: Will the LD3985 will turn on in this circuit?

texts:
This is a beginner's question.
In the LD3985 datasheet I found this example:

I made this circuit:

If i put a capacitor between INH pin and GND, will it run correctly or should I remove this capacitor?


texts: Air Core Transformer & Ferrite Core Transformer

texts: What is the differnce between a transformer having ferrite core and another transformer without any core (air core transformer).How these two affects the output power and leakage flux??


texts: Reliable antenna matching design of quadrifillar helix

texts:
I have simulated this antenna :

I found its impedance, I know I have 50 ohm transmission. I decided to match these by discrete part in feed point, The match circuit is

I want to ask from those who are experienced that is this way of design acceptable and reliable? If not what is the correct way. Note that I have no analyzer. I just have oscilloscope and multi-meter. Also I don't know how I can make current balun?


texts: Can I use a battery protection circuit for a 3S 18650 with a LiPo 3S pack?

texts:
I am looking into getting a battery protection circuit for the 3S LiPo pack I am planning on using in my project. Max current draw will be 5-6A. Since I think it's more efficient to buy something prebuilt I was looking on aliexpress for something that I could use.

However most of the parts sold there are specified as for 18650 battery pack usage. Here is an example:

Protection circuit

Can I use this kind of circuit with a LiPo pack? Do I need to connect the battery + to B+, the battery - to B- and then connect 2 wires of the balance cables to B1 and B2, or am I completely wrong?

Since the circuit is rated a 8A it will be more than sufficient for my needs

Thanks


texts: Does this H-Bridge need any supporting circuitry?

texts: I'm still pretty new to transistor stuff, so excuse the n00b question. I'm looking to use this h-bridge to toggle a latching solenoid valve, where I need to toggle it on/off with +/- 6VDC. I've used a SN754410 before, and there the control lines could go straight to my arduino. I assume here I can run the 4 gate lines to 4 separate arduino pins, and control the polarity that way?


texts: A good and valid example of Common Collector BJT

texts:
I am analyzing a common collector BJT as an amplifier using LTSpice. I have made the following circuit and I am not getting the exact characteristics which I should have got.

Is there something wrong in this circuit? It is clear that the polarity of the batteries is correct and we have to vary them to obtain the characteristics. Please help!!


texts:
I'm trying to infer the usage of a RAM block of my FPGA, but I fail to understand what are the hints needed. I use Synplify Pro as my synthesis tool.
If I'm not mistaken, this is a dual port synchronous RAM that I need to infer.

library ieee;
    use ieee.std_logic_1164.all;
    use ieee.numeric_std.all;

entity fifo is
  generic(
    constant DATA_WIDTH : integer;
    constant FIFO_DEPTH : integer
  );
  port(
    clk       : in std_logic;
    mmc_clk   : in std_logic;
    reset     : in std_logic;
    spi_done  : in std_logic;
    rx_data   : in std_logic_vector(7 downto 0);

    write_en  : in std_logic;
    read_en   : in std_logic;

    data_out  : out std_logic_vector(7 downto 0);
    data_in   : in std_logic_vector(7 downto 0);
    empty_o   : out std_logic;
    full_o    : out std_logic;

    level_o   : out std_logic_vector(7 downto 0)
  );
end fifo;

architecture arch of fifo is

signal mmc_clk_prev, mmc_clk_i : std_logic;

begin

-- Memory Pointer Process
fifo_proc : process (CLK)
    type FIFO_memory is array (0 to FIFO_DEPTH-1) of std_logic_vector(DATA_WIDTH - 1 downto 0);
    variable memory : FIFO_memory;

    variable head : integer range 0 to FIFO_DEPTH - 1;
    variable tail : integer range 0 to FIFO_DEPTH - 1;

    variable looped : boolean;
    begin
    if reset = '1' then
        head := 0;
        tail := 0;
        looped := false;
        full_o  <= '0';
        empty_o <= '1';
    elsif rising_edge(CLK) then
        if (read_en = '1') then
            if ((looped = true) or (head /= tail)) then
                -- Update data output
                data_out <= memory(tail);
                -- Update tail pointer as needed
                if (tail = FIFO_DEPTH - 1) then
                    tail := 0;
                    looped := false;
                else
                    tail := tail + 1;
                end if;
            end if;
        end if;

        if (write_en = '1') then
            if ((looped = false) or (head /= tail)) then
                -- Write Data to memory
                memory(head) := data_in;
                -- Increment head pointer as needed
                if (head = FIFO_DEPTH - 1) then
                    head := 0;
                    looped := true;
                else
                    head := head + 1;
                end if;
            end if;
        end if;

        -- Update empty_o and full_o flags
        if (head = tail) then
            if looped then
                full_o <= '1';
            else
                empty_o <= '1';
            end if;
        else
            empty_o   <= '0';
            full_o    <= '0';
        end if;
    end if;

    if head-tail >= 0 then
        level_o <= std_logic_vector(to_unsigned(head-tail,level_o'length));
    end if;
end process;

end arch;

What am I missing?