All Questions
172,722
questions
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Discrepancy in theoretical vs measured gainbandwidth in LTSPICE ideal OTA
I am using a very simple model to show the unity gainbandwidth of a closed loop sample and hold with a closed loop gain of 2. One would expect an ideal OTA to have a GBW independent of rout as GBW is ...
- 1,672
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votes
0
answers
6
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Implementing A/D conversion circuit to a DIY clamp meter
I was looking for cheap clamp meter projects and found this one: DC non invasive current clamp for oscilloscope DIY.
After reading about this project, I noticed that it had a BNC output to read values ...
- 35
0
votes
0
answers
10
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How can I generate a sawtooth waveform?
I am trying to generate a sawtooth waveform with either an integrated circuit or by building my own circuit.
I need to be able to vary the frequency.
- 601
0
votes
0
answers
10
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How are S-Parameters and Reactance related, can one be calculated from the other?
I know that, for example, \$X_L=2\pi f L\$ will calculate reactance of an ideal inductor, but can this be calculated for a real component model? Given the S-Parameter values at some frequency from an ...
- 774
1
vote
1
answer
22
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Resistive Moisture Sensors, What is the purpose of the 2N3904 Transistor in the Sparkfun Circuit?
the two circuits below do the same things as far as I can tell, they both measure soil moisture using resistive sensing. However the one from Sparkfun is using a 2N3904 transistor, since the voltage ...
- 11
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votes
0
answers
21
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Power/Sense line connections when a relay in path
I need to connect a power supply instrument with (power and sense line) to my IC, this IC is separated by a relay.
Can I connect/tie the sense line of the instrument close to IC in the layout (as ...
0
votes
1
answer
43
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Smoothing potentiometer output
I am building a paddle controller for my Commodore C64. Basically all you need is a 470k (or 500k) potentiometer connected to two of the joystick wires. Internally, the C64 has capacitors through ...
- 101
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votes
3
answers
50
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Integrator circuit - no DC path from output to input
Someone told me that this circuit does not work unless there is DC bias path in the feedback.
Because the op-amp is operating open loop for DC.
Someone also told me that the input transistor pair of ...
0
votes
0
answers
26
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Samlex power inverter PCB wiring schematic or test points
I am trying to find a wiring diagram or voltage test points for a Samlex 1500 watt PST150S-12A inverter board. Losing a/c output, have found a possible short on board. 2 of the 8 output mosfets have ...
0
votes
1
answer
29
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Time invariant system with sinc impulse
Given said system, the impulse responses for the LTI systems \$H_1,H_2\$ are :
$$ h_{1}\left(\tau\right)=\frac{\sin\left(\omega_{1}\tau\right)}{\pi\tau}d\tau,h_{2}\left(\tau\right)=\frac{\sin\left(\...
- 101
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80
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Small capacitor in series with battery pack - Why/how? [closed]
I have a device with a 12V battery pack (it's actually eight AA batteries in a harness.)
In taking it apart, I see that it has a small capacitor in series with the positive side of the supply. So, ...
- 121
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votes
0
answers
62
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Looking for inventer and/or name of fast sorting algorithm
Back in 1992, when I was a grad student in the Computer Science and Engineering Department at the University of Washington, my faculty advisor told me of a sorting algorithm that takes as input N ...
0
votes
0
answers
36
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How to improve a Tesla coil?
I've recently built a relatively big Tesla coil. It is a larger version of the Slayer exciter but with 2 big MOSFETs. The same circuit, with a smaller coil produced small arcs without a top load, and ...
- 11
0
votes
3
answers
43
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Need to limit the torque on a spooler
I'm a newbie to DC motors. I'm trying to use a geared DC motor of 150RPM 70Ncm torque to pull in rope on a small spool. The rope is being released by other equipment. This rope is being released at ...
- 1
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votes
2
answers
28
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Same variables and different values on instances
I have searched on google but I have not found a way to put different values in the variables of the same symbol placed more than once.
Each component "X11, X12..." etc, are the same, and ...
0
votes
1
answer
28
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Proteus LCD doesn't display characters
I've been trying to show some characters on a LM015L LCD but I wasn't able to do it.
I've written the following code in C:
...
- 101
0
votes
2
answers
41
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Confused regarding gain margin and stability
I plotted the bode plots of the transfer function:
G(s)= 2.123×10^6 ((0.105s+1.01))/(s^2 (s+12566.37) )
It is as follows:
As can be seen, it shows the gain margin as negative infinity, however loop ...
0
votes
0
answers
28
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Current source controlled via PWM
Trying to simulate a sensor that acts as a current source. This sensor generates 2 current values:
10mA (low signal)
20mA (high signal)
I will be using an STM32F4 micro - PWM output pin to try to ...
- 1
1
vote
1
answer
75
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How do you get from the low-pass filter formula to the code?
I am just wondering how the author deduced this code from this formula. This is the step response of a Low-pass filter.
$$v_{out}(t)=V_i\cdot(1-e^{-ω_0\cdot t}), \text{ where } ω_0 = \frac{1}{R\cdot C}...
- 301
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votes
2
answers
100
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Need 64Hz square wave green LED driver for a mosquito zapper
I have several 10 watt COB (Chip-on-Board) green LEDs which apparently are the best color to attract mosquitoes if driven at an ideal pulsing square wave frequency of 64 Hz.
I was going to use a ...
- 11
1
vote
1
answer
38
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VHDL: How to use records as PORTS with IN and OUT parameters?
Is there a syntax where one can use a record type in a PORT declaration, but specify that certain members of the record are IN ...
- 13
0
votes
0
answers
49
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Why does this solid state relay circuit work sometimes and not other times? (stuck closed)
It's a very simple open collector output from one device driving a solid-state relay (VO1400) in another device. You can see the power transistors (BS868) that drive OUTn.n in the circuit diagram. ...
- 1
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votes
2
answers
43
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5V protection circuits
For my project, I'm using this solar shield in order to use some solar panels and a battery to power my Arduino. In order to protect the solar shield (where the maximum solar input is 6V) I would ...
- 109
0
votes
2
answers
38
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HDMI: Can a computer still detect a monitor properly if some of the TDMS pins/wires are damaged? [closed]
Can a faulty HDMI-cable with damaged TDMS pins/wires still work to the extent that the computer can still detect the monitor, but the monitor just will not display anything (except for no signal)?
- 101
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0
answers
30
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How to correctly terminate a TTL line between two ICs?
I am designing a circuit to convert a 5ns ECL signal to an LVTTL signal of >10ns. The SY100ELT25 is used to convert the ECL to 5V TTL which is then fed into the SN74LVC1G123 to further reduce the ...
- 65
-1
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0
answers
26
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Clap sensor Proteus simulation issue
I've been trying to connect an electret microphone into this circuit, although none of the imported electret microphones work.
The circuit is designed to keep the LED open for about 1 second by the ...
- 1
-1
votes
0
answers
43
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Maximize the voltage gain of the CE amplifier [duplicate]
I have a problem in maximizing the voltage gain in given CE amplifier. The problem is to determine the values of R2 and R3.
What is the process of getting the values of R2 and R3?
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-3
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0
answers
41
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Construct a 16x8 memory [closed]
I am very new to this and have no idea how to proceed, I have looked at tutorials.
Someone help me. : )
I have to design and simulate a 16x8 memory on logisim.
-4
votes
1
answer
40
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In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?
In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?
https://ibb.co/c3X1NRS
-4
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0
answers
41
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1
vote
0
answers
24
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How to properly handle mixed RF/digital design in HFSS 3Dlayout
I have a big design imported from Altium into HFSS 3DLayout with several RFIC that I want to simulate. RF and Digital (SPI) nets are included in this design.
I'm interested mainly in the RF side of ...
- 121
-2
votes
0
answers
44
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Which are better and more accurate alternatives to LMV324 by Texas Instruments? [closed]
I need LMV324 form my electronics circuit, but it is not available in India, and someone said there are more accurate quad amplifiers available than this. Can someone tell more quad amplifiers with ...
- 69
3
votes
2
answers
84
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Measuring the reflection coefficient \$\Gamma\$
I want to measure the reflection coefficient.
I have the following circuit:
With these measurements I get the following graphs:
Is the reflection coefficient the negative peak of the RED signal ...
- 187
0
votes
0
answers
31
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Alkaline vs lithium vs other battery for specific use [closed]
I would like to know which type of battery would be better for a device with the following specifications:
Bluetooth access system control (BLE)
Device will have a low duty cycle, being most of the ...
- 143
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votes
0
answers
29
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Why is the change in reactive power not equal to the line reactance drop?
I am working on an equivalent network of a two bus system right now.
I know the \$P\$, \$Q\$ and power factor at Bus 2. Bus 1 is taken as a slack bus (\$V = 1 PU\$, \$\delta\$ = 0). Using iterative ...
- 101
-3
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0
answers
63
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What will be the new value of Vy? [closed]
It is clear to me that Vx will charge upto 3.4V and Vy will also be 3.4V but what will be the value of Vy if I increase the gate voltage of second MOS to (say) 4.2V?
Also, if possible kindly attach ...
1
vote
0
answers
47
views
Mitigating FET current spikes in an SMPS buck converter
I'm currently designing an SMPS buck converter that converts 311VDC to 60VDC at 10 Amps maximum load. I'm using ESP32 for the PWM control, and IR2110 for the switching driver. The switch I'm currently ...
- 111
-1
votes
1
answer
68
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Is there a manufacturer that produces an analog ohmmeter specifically for [closed]
Does anyone know of a manufacturer that produces a specific type of analog ohmmeter for testing the automotive relays equipped with silicon diodes ? I have heard that it is a newer type and has an ...
- 1
1
vote
1
answer
53
views
Identify number of strings in Philips 14.5W LED PCB
Is it possible by just looking at the attached image whether the LEDs are in a single series circuit, or whether they're configured in series/parallel? The image is not great but I tried to highlight ...
- 113
5
votes
5
answers
229
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How to find a fast optocoupler (or how to read the datasheet)
I am looking for an optocoupler that can sustain a 400kHz signal. Now the question is how can I find out from a datasheet whether it does?
Looking at a typical PC817 datasheet I see the following ...
- 151
0
votes
1
answer
25
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Singular Value Decomposition MIMO
Singular Value Decomposition in MIMO Spatial Multiplexing requires knowledge of the channel state information at both the transmit and the receive and allows parallel independent data streams to be ...
- 341
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0
answers
29
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I need help on circuit of 28v DC with 6 amp flow + superimposed higher volts of small wattage, so as 100v present with amps from first source [closed]
I need help to redo my circuit of 28v DC with 6 amp flow out, from DC converter, and hooking in Parallel, with with superimposed small 30 watt module, as 100volts DC so as the small end electrodes ...
- 1
0
votes
1
answer
59
views
Different power supplies
I have an the following components:
Arduino Mega (9V)
8 relays (5V)
4 AC/DC voltage sensors (5V)
SIM800L (4.1 V)
How many power supplies do I need on my circuit board?
Is it good idea to use one ...
- 111
0
votes
1
answer
50
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Grounding sensors to large bodies
I've attached a diagram of what I'm talking about.
I have a large (600x300x10 mm) aluminum block in which I place thermistors to monitor the temperature distribution in the plate (in a standard ...
0
votes
1
answer
58
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How to distinguish which buttons have fixed on/off positions similar to a flashlight button?
I'm searching for a button/switch similar to one on a common flashlight: you click the button to turn the light on, then eventually click it again to turn off. Example clip of Button (Adafruit / ...
- 115
0
votes
0
answers
19
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Solar panel to power load first charger second [closed]
I have small cold frames ventilated w/ a muffin fan powered by my panel through a buck/boost board to a temp controller board. I want to power a charge controller when the temp controller is not ...
- 1
0
votes
0
answers
39
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Running 400 Hz, 380 V spindle motor on 220 V, 3-phase VFD
I just (mistakenly) purchased a 380 V (400 Hz) spindle motor and I have a 220 V, 3-phase VFD. The manufacturer said the winding is a special configuration that performs equally well with either ...
- 1
-2
votes
0
answers
10
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LoRa spreading factor
How can I calculate the spreading factor for Semtech SX1261 transceiver? And how Spreading factor is related to LoRa modem setting along with Bandwidth and Code Rate?
- 7
1
vote
1
answer
37
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Why my ESP32-CAM won't power up with 5 volts?
I'm new into electronics and I decided to power up my ESP32-CAM with a 9V battery instead FTDI programmer (I measured it, it gives 5V to ESP32-CAM). I thought if I reduce voltage to 5V with mini ...
- 11
0
votes
0
answers
20
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DC Motor driver with Recuperation Design
This is a design idea for a DC motor driver with good energy recuperation. I have a mobile machine, that includes a 250W motor with a heavy rotating mass and many spin up cycles during use. The ...
- 236