All Questions
172,717
questions
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635
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Explain the operation of this circuit
I am studying this application circuit to design the biasing circuit.
I have understood the explanation up to a certain point, but I am stuck at the "Gate bias supply circuits" section.
It ...
CommunityBot
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0
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3
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Is this two-tone oscillator a smart design?
I am fiddling a bit with building some kind of programmable sound generator using simple components. I got something more or less working now as a proof of concept:
Here, the 555 is wired as an ...
- 145
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votes
1
answer
31
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How worried should I be about a short circuit lasting a couple nanoseconds?
Say I have two driver gates hooked up to each other in the following arrangement:
In theory when A goes low, for a brief amount of time B will be shorted while the 7404 inverter gate switches. Around ...
- 20.4k
-1
votes
1
answer
17
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I am looking for a 5V DC-DC converter that I can use in industry [closed]
I am developing an industrial project as an amateur. I am designing a system consisting of ESP32, Nextion HMI, Barcode Scanner, Sensors. The system draws about 1.5A of current.
So far I have been ...
0
votes
0
answers
3
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Ipad air repair botched?
I have an Ipad Air and i have fitted a new battery and digitiser for it. I decided to do a test of the ipad to see if the new battery and digitiser worked and while the ipad does turn on, it turns off ...
1
vote
2
answers
103
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How to make a MHz-fast, 5 volt thyristor with discrete components?
Off-the-shelf thyristors are optimized to switch at mains frequency, - 60 Hz in the U.S.A. In my application, I need MHz speeds, 10 to 20 watts, 5 to 10 volts.
Is it possible to emulate thyristor ...
- 134k
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0
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29
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How can one calculate at surface the electric or magnetic field strength for 50Hz 240VAC wire at 1 meter depth?
How can one approximately calculate at surface the electric or magnetic field strength for 50Hz 240VAC wire buried at 1 meter soil depth for a given current?
Say in sandy clay soil with no mineral ...
- 155
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votes
2
answers
62
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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 ...
-1
votes
1
answer
25
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AM single sideband modulator
I am doing a AM single side band modulator that can help to produce a single sideband from a spectrum analyzer. But now even i had follow the rules to build a modulator, the output still not showing a ...
- 256
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votes
1
answer
18
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Altium part has hidden rectangles causing it to overlap other components
I downloaded an Eagle LBR file of an RP2040 WIO and imported it into Altium. When adding it to my PCB, I cannot fully move the component into the corner as it thinks its footprint is bigger than it ...
- 584
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votes
3
answers
610
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Using an Arduino to read data from an ADS1113
I have an ADS1113 ADC connected to an Arduino using the I2C protocol. I'm just trying to read the analog data from the ADC.
I have 5 volts connected to the AIN0 and AIN1 inputs. When I check the ...
CommunityBot
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votes
1
answer
191
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spike in the Full bridge SMPS
I have a full bridge SMPS and I am measuring the voltage across the output´s diodes on the secondary side.
As you can see the voltage spike changes by changing the output current, for example at zero ...
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1
vote
3
answers
92
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How can the energy produced by a generator be fed back to the motor that rotates the generator?
The drawing below shows an induction motor (IM), powered from the grid through a variable frequency drive (VFD). This IM, through a gearbox, rotates a permanent magnet synchronous machine (PMSM) ...
- 179
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votes
2
answers
20
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ESP MCU, directly drive BT136
Hello I have BT136 and ESP8266-NodeMCU-12E, I have tested BT136 that if you apply 1.2V form AA cell to Gate and T2, this result T1, T2 short for 220VAC. My question is can I use my NodeMCU's D2 pin (...
- 526
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vote
2
answers
32
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Using complex impedance
Any help getting the answer shown here?
I have tried adding the complex impedance of L and R in series and then adding that to C in parallel. I'm not super sure about that last step, and then ...
- 379k
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votes
2
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475
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How to connect/terminate differential CML logic outputs to single ended ECL logic input?
If I want to use a CML differential gate's (Ex: SY58051AU) output as the enable ECL input for an ECL counter(EX: MC100EP016A), whats the best way to connect the output to input? I think I need to use ...
CommunityBot
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1
vote
1
answer
21
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MCP23017 open drain interrupts not working as expected
I have multiple MCP23017 ICs with their interrupts all connected in serial. The interrupt pins are configured to be open-drain.
All the A port interrupt pins are connected together and all the B port ...
- 87.1k
1
vote
1
answer
47
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What does LSB mean in PWM?
I have this PWM exam preparation question in Computer Engineering where it says "What is one V_LSB?". However we've discussed nothing about LSB in the PWM section.
What does it means?
- 2,287
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18
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6
votes
2
answers
2k
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Do neon signs emit x-rays?
I'm interested about whether or not a conventional neon sign such as this one could emit x-ray that could be harmful.
The sign that you can see in the picture is just below my office window so I'm ...
- 261
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votes
1
answer
32
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Circuit for charging a coin cell battery while also powering main circuitry
I am looking to design a USB rechargeable device that feature a small microcontroller set up to run at low clock frequency driving a few LEDs. I'd like to power it off a 2032 coin cell battery or ...
- 57.5k
2
votes
2
answers
519
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Integral of phasor
Say \$v(t) = V_m\cos(\omega t+\phi)=\Re[V_me^{j(\omega t +\phi)}] = \Re[Ve^{j\omega t}]\$,
where \$V_me^{j\phi} = V\$.
Integrating gives
\$\int\limits_0^t v(t)\,dt = \Re\int\limits_0^t Ve^{j\omega ...
- 175
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votes
0
answers
34
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Could isopropyl damage a PCB?
I cleaned a PCB with isopropyl alcohol, 75%. When I turned it on, something strange happened. The microcontroller GPIOs that drive the LEDs started to behave like they have relatively low resistance, ...
- 57.5k
0
votes
1
answer
23
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Hiw to solve "no simulator model" in Proteus?
I would like to do a simulation using the SPV1050 in Proteus, but Proteus says "no simulator model." What does that mean?
Is it only for PCB design , so not suitable for doing simulation to ...
- 57.5k
1
vote
1
answer
153
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18650 Cell boost converter to 4.8v (not 5v)
I have a torch in which 3 AAA cells are put in (1.6 (new AAA) * 3 =4.8v). The problem is these are not long lasting and i have to change them after few days. What i am looking for is a rechargeable ...
CommunityBot
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2
answers
61
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Please help to verify my explanation for the amplitude and help to explain why the amplitude diminishes over time
I have the circuit below which consists of a series resistor followed by a parallel LC circuit:
It produces this output waveform:
From the simulation, I know the waveform has a frequency of 10Khz ...
- 57.5k
2
votes
2
answers
60
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Is this single transistor interface good enough for this relay-control?
I need to turn ON/OFF an 12V 10A SMPS supply by a relay. I want to switch the SMPS via its line input using a microcontroller. I need a normally open non-latching magnetic relay such that the SMPS ...
- 1,349
0
votes
1
answer
73
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Thevenin's theorem for Voltage divider bias
I am calculating the base current of transistor Q1. To simplify the circuit equations, I applied the Thevenin's theorem and converter V1 and R1, R2 into Vth and Rth as shown in the image.
Vth= V1x(R2/...
- 175
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0
answers
5
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HC 06, arduino mega 2560, not responding to AT commands
This is the circuit i built, following a guide on youtube.
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-1
votes
1
answer
41
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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 ...
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1
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1
answer
152
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How to draw 5V power from KNX bus without disturbing the communication?
I've got a KNX-like bus system in my house. (Specifically it's ABB/Busch Jaegers free@home, which I think is based on KNX, for this post I will keep referring to it as bus or KNX bus) This bus system ...
CommunityBot
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0
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26
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Circuit help needed on converter DC with superimposed higher volts, so as 100 V present with same amps from first source [closed]
I need help to readjust my circuit of 28v negative DC with 6 amp flow out, from DC converter, and hooking in PARALLEL, with with superimposed small 30 watt module, as 100 volts negative DC, so as the ...
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2
answers
506
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What would i change about this diagram to power and regulate this motor to make this a working model
what if the battery was 12v? would this be a working model? a previous comment suggested a BJT, and to regulate the BJT with a potentiometer.. what is a BJT?
i am looking to get as small of ...
CommunityBot
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votes
3
answers
269
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Monostable circuit with 1 hour high output
I want to build a monostable circuit (a circuit with one input as a pushbutton), that will output logic '1' when the pushbutton is pressed for one hour (with the least error possible) then go back to ...
- 2,073
2
votes
1
answer
290
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Signed Integer Division Optimization
I've implemented a division algorithm on an FPGA using the long division algorithm. My implementation does not use pipelining, but works iteratively and requires very few logic elements since the ...
CommunityBot
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2
votes
1
answer
42
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Second order low pass filter: two 1st order filters not-immediately cascaded
A second order low pass filter (LPF) can be made by cascading two active LPF (an RC network + opamp.) What happens if, instead of immediately cascaded, an active LPF acts at the input (buffer) of a ...
- 57.5k
3
votes
3
answers
218
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How is the word "kilohm" pronounced traditionally?
Had to ask this in electronics, would like to hear this from people who have been involved. I am not a native English speaker, and I couldn't find a definitive answer online: there are too many ...
- 29.4k
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votes
0
answers
30
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Active inductor
I am designing active inductor using OTAs (Transconductance amplifiers) and have a problem writing an equations.
I wrote two equations for nodes V2+ and V2- and input current Iin.
$$ 0=sCV^+_{2}+g_1(...
4
votes
2
answers
1k
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LDR component obsolescence
The light dependent rrsistor (LDR) that I use in MintyTime, Excelitas Tech VT93N2, has been discontinued by the manufacturer. I'm having trouble finding a comparably priced (e.g. < $0.50 @ 100+) ...
3
votes
2
answers
164
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Interview Question
This Circuit was given.
I know every component of this circuit individually, I know feedback and gain margin and transconductance amplifier.
But the problem is how to start?
first, I was thinking to ...
- 7,177
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2
answers
48
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PNP TIP126 transistor hot to touch while in use
I have a 7-segment mechanical 'vane' display andbgot it working using a circuit originally suggested to me here. The diagram below is a slightly modified version.
Each vane draws around 0.2A of ...
- 57.5k
-1
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0
answers
27
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What is the total filter and output capacitor rating in this circuit?
Is the total filter capacitance 2.2uF?
If so, is the output capacitor 82.4uF * 20?
- 57.5k
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votes
1
answer
42
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Automatic dark detector: base voltage
Here we have the typical “automatic dark detector” circuit:
Let’s assume LDR=5Kohm with light, and LDR=2Mohm in darkness, the battery is 12V instead of 9V, and the transistor has a forward voltage ...
- 12.5k
-2
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0
answers
18
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Repair advice for an LG 49UH620V with flickering picture (repost) [closed]
After changing channel, the picture on my LG 49UH620V television started doing this flicker. I tried reseting the software to factory settings, then tried leaving it unplugged over night, and still no ...
0
votes
0
answers
34
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FT232RL Chip is not working (USB to TTL)
I used an FT232RL chip to make a USB to TTL converter using the schematic below.
Although I can send a message and the TX LED is lightining up, I cannot receive any messages.
Can anyone see a problem ...
- 13.2k
-1
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0
answers
24
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Looking for a circuit board simulator with Arduino support [closed]
I am using Tinkercad circuits to hook up Arduinos with simple circuits and run the simulation.
I like it very much, but the library of Tinkercad components very soon became too small and was the ...
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1
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463
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What is the maximum possible temperature a MOSFET can reach?
I'm choosing a switch for a power supply design. I would like to know the highest temperature the MOSFET can reach. The switch that I'm using is DMT3020LDV.
An input having 24 V and 8 A is supplied to ...
CommunityBot
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0
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66
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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
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0
answers
29
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GPIO basically not working on STM32401CCU6 Blackpill
As a newbie I switched from Nucleo to Blackpill recently (STM32401CCU6 ) and after an overally good start I faced a wall.
It seems like GPIOs are... dead for some reason:
HAL_GPIO_WritePin/TogglePin ...
- 115
2
votes
2
answers
105
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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}...
- 57.5k