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1answer
14 views

How to Find Output Resistance [closed]

How would I calculate the output resistance of this circuit? (Ro is defined by looking in from vo) Thanks!
0
votes
1answer
21 views

Saftey regulations of multiple 1mW lasers

AFAIK devices containing exposed 5mW lasers are illegal without a license, but those containing 1mW lasers are. But how about a device with ten 1mW lasers? Is it still a safe and legal device? The ...
0
votes
0answers
11 views

Can a thyristor regain its forward/reverse blocking capability if the current through it is “instantly” brought to zero?

I am imagining a situation where we have several series-connected thyristors, say 10, each that can block a voltage of 100V. So, the ten series-connected thyristors together can block a total voltage ...
1
vote
1answer
19 views

How can I reattach tiny wires to a tiny circuit board? [closed]

These power supply wires broke off due to my carelessness. How can I reattach them without soldering?
0
votes
1answer
21 views

Why did the designer of this flyback circuit choose to set the oscillation frequency as high as possible with the smallest resistor tolerated?

This circuit uses a current mode controller with an oscillation frequency response of: In the circuit, the designer chose to use a 10nF cap, with a 680 ohm timing resistor, which according to the ...
0
votes
0answers
18 views

explanation of DC ceiling fan motor and hum and noise [duplicate]

I asked a while back why does a ~$150 120vac electric ceiling fan, above my bed at home, hum and agitate me. Didn't come to a 100% solid reason but I believe it's due to that motor being a brushless ...
0
votes
0answers
17 views

TF-Mini S lidar not sending any serial data

I have a TF-Mini S Lidar. I have hooked it up to my arduino like so: (Above image from learn.sparkfun.com) And have uploaded this code to the arduino board: ...
3
votes
1answer
41 views

What prevents the lead attached to a semiconductor from forming Shottky junction

What prevents lead attached to a piece of semiconductor (for example in BJTs and FETs) from forming a Shottky junction?
0
votes
2answers
56 views

What's the name of this electrical connector?

What's the name of this electrical connector?
1
vote
2answers
33 views

Identify molex connector

Anyone know what kind of connector is this?The female connector size is around 18x7 millimeters
0
votes
1answer
33 views

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

The components: a laptop, a blue pill board, a +5V power supply(taken from old PC). I have a blue pill board(stm32f103c8t6 mcu). Schematic here. I connect my laptop to the blue pill board via SWD ...
-1
votes
1answer
41 views

Use capacitor as keep-alive for alarm clock [closed]

I would like to integrate a capacitor onto the power supply of an alarm clock to prevent the flashing "12:00". Which would be the best way to implement?
2
votes
1answer
36 views

Need Help Creating SATA Power Cable for Lenovo C540 AiO

I need expert help. I have an old Lenovo C540 AiO desktop that I am trying to salvage. This model is prone to a failure in the SATA power cable, at the HDD connector end. I have found video guides on ...
0
votes
3answers
61 views

How can i make a frequency dependent switch?

Is it possible to make a circuit/switch that turns a relay ON whenever there is a certain RF frequency applied and keeps it OFF for all other frequencies. The RF signal should not carry any ...
0
votes
0answers
31 views

How can i protect N-MOSFET from failing

i have made simple inverter circuit with z44 MOSFET but circuit work for minutes and the primary coil start heating then shorting finally damage the MOSFETF, it is my 6th time facing this issue. i ...
0
votes
1answer
37 views

Ferrite core StepUP Transformer Design

So, I want to make a High-Frequency Ferrite transformer that can convert my 150-volt peak Square wave into 100000 Volt Peak. I am using UUR6440 Ferrite Core. Material is CF139 https://www....
0
votes
1answer
36 views

FET electrode convention?

Are there any conventions that allow one to tell which electrode is source and which one is drain?
-2
votes
0answers
27 views

2 Phase servo motor operation

Can somebody explain to me how 2 phase servo motors move loads? Have researched online but all explanations are very brief, a main winding connected to an AC source, a control winding with variable AC ...
0
votes
1answer
23 views

How to compute Rth for this circuit using OrCAD PSpice

Take a look at this circuit The question asks to find Rth and Vth between a-b terminals. Hand calculation yields Rth=3.857 and Vth=4V. With OrCAD, the result is shown below using Bias Point ...
0
votes
1answer
36 views

Linear regulator with tab at ground

I am searching for a linear regulator with tab connected to GND instead of Vout because it would be easier for thermal management. Unfortunately, all linear regulators seem to have their tab connected ...
0
votes
1answer
39 views

Do I need to suppress ringing in a flyback converter?

I am about to design a flyback converter. As all flybacks with no extra measures it has some ringing. You can see that ringing in this example from -1µs to 4µs: This ringing can be surpressed by a ...
1
vote
0answers
41 views

Schmitt trigger output waveform coming as sinewave

I am new to Proteus. I tried simulating an easy circuit which was a Schmitt trigger using an op-amp. After simulation, the output waveform was an sinewave instead of rectangular wave. Any idea where I ...
-1
votes
0answers
35 views

Disadvantage of an AC tachogenerator

I was researching on AC tachogenerators and how they are used for velocity feedback to reduce load oscillation. However I came across a disadvantage of using it, it always will have an output even ...
0
votes
2answers
48 views

Logic buffer design

Logic buffer is usually depicted like this: But can this work equally well? And if it's not the case, why not?
1
vote
1answer
22 views

MPU9250 IMU wearable design considerations and device address problem

I need to use 12-16 mpu9250 IMU for wearable design. Each IMU will be placed different places on the body. Therefore, I want to read data from each device by using I2C interface. However, problem is ...
0
votes
1answer
31 views

Not matching 50 ohm impedance

For my RF circuit (868MHz), I need 50-ohm impedance. When I calculate the impedance as PCB manufacturer layer stack-up, the impedance would be 66 ohms. How does this affect my RF circuit performance? ...
0
votes
2answers
52 views

Confusion in current calculation

I'm confused about two different approaches for current calculation through a 5 ohm resistor. The 5 ohm resistor is in parallel with a voltage source so the current through it should be 2 amperes. ...
0
votes
0answers
22 views

Low Power Toroidal Conductivity Sensor Inconsistent Values

I have been trying to build a low power toroidal liquid conductivity sensor using the principle given in this image. This link has more information about the principle behind the sensor. What I have ...
0
votes
1answer
28 views

PCB designing of GSM module

I want to design PCB of a GSM module. Inside a GSM module there is a place to put a (mobile cellular ) SIM card. And then this GSM module can send SMS text messages to different phone numbers. ...
0
votes
1answer
25 views

E/I inductive position transducer sensing device operation

so I have been doing some research on AC servo position flight control surface systems an was trying to find the component used to set the pilot's input command. Found out that a E/I inductive ...
-3
votes
0answers
27 views

Ethernet switch- Communication

I have a small doubt on using Ethernet switch. Query: Below is my setup will the communication happens between Board1 & Board2 through ethernet switch.
-1
votes
0answers
26 views

Trying to power up Amazon Echo in car

So I want to connect my car with Amazon echo show. Currently I connected it to the 12 v power output( cigarette lighter ), however when the car is started the power is interrupted ( while starting the ...
1
vote
2answers
56 views

Opto-isolation amplifier output is too off

(As a follow-up to an earlier question answered by the community - thanks!) So I've got the test circuit setup using the HCPL 7520 (datasheet) now and planning to use an Arduino Uno to measure the ...
0
votes
1answer
34 views

Differential gain of op amp

So I was reading the chapter on Op Amps in Microelectronic circuits by Sedra, Smith, the topic on Differential Amplifiers to be exact. Here's the amplifier: https://i.stack.imgur.com/3qWzi.png To get ...
0
votes
1answer
32 views

Non-inverting unity gain buffer appears to be inverting

I have constructed a circuit which uses two non-inverting unity gain buffers on one chip as stage seperation. I'm using a TL072CP chip with dual op amps on it and have followed the datasheet design ...
0
votes
1answer
37 views

4 layer buck converter layout

What is the standard layout for a 4 layer PCB that everyone follows for a buck converter or similar? I was planning to go like this: Signal Vcc GND Signal Since inductors and FETS are noisiest of ...
1
vote
3answers
61 views

How does the Colpitts oscillator provide positive feedback?

This is a Colpitts oscillator in a common-emitter configuration: For oscillation to occur, there must be a positive feedback. But I'm confused how can this oscillator provide a 360° degree turn for ...
0
votes
2answers
32 views

XR2206 Function Generator Kit on LM2917N-14

Please forgive my bad language I make Vehicle Speed Indicator with LM2917N-14. I tried it with cheap XR2206 Function Generator and NE555 Variable Square Wave. With NE555 LM2917 working properly, the ...
0
votes
2answers
43 views

USB Cable wiring

I have this usb cable from my old samsung phone. There's four wires which is red, white, green, and unshielded wire. Now these wires came from foil like cover which is surrounded with another ...
0
votes
2answers
21 views

Importing Altium schematics to a PCB is placing some components on a forbidden and an unaccessible area

I was using Altium 16 and generating PCB from schematics with no room generation. I have created my components library by mostly using "ultra librarian" files. I do these steps as many other ...
0
votes
5answers
57 views

Voltage comparator - how to get a stable voltage reference from a battery

I'm trying to build a circuit which will be used to monitor the voltage of Li-ion battery. The voltage comparator I'm using is LM393. Since the whole circuit will be powered by, it the battery will be ...
0
votes
0answers
20 views

Linear motion (quiet, variable speed)

I want to use a raspberry pi or arduino to create linear motion, back and fourth, my current goal is to make the pushing part for a baby rocker, but also a swing-rocker as a next project I have looked ...
0
votes
0answers
16 views

Motor consumption with 1V vs 3V w/ 90% PWM

Using a DC motor, I can reach about 1200rpm using 1V/1A (laboratory style power supply) However, if I use 3V input and a PWMized MOSFET, I need a duty cycle of about 90% to reach the same rpms and the ...
3
votes
2answers
145 views

Are fins necessary/required for cooling in a closed room

i am trying to design an efficient cooling solution for my project. I planned placing a IoT computer in an aluminum housing which is completely closed. In this case, do I really need fins and large ...
0
votes
0answers
11 views

Polarization loss factor for antennas

What would be the polarization loss factor, if transmitting antenna is circularly polarized and receiving antenna is linearly polarized, but they are aligned in such a way that maximum radiation ...
0
votes
0answers
17 views

Photo-resistor and leds

I'm trying to build some system that would detect light and turn a 12v led strip ON. The only power that I have available is a 9v battery. I found some Arduino compatible boards but it seems overkill ...
0
votes
0answers
26 views

How does a USB-C to Lighting Adapter work / How to replace them?

So, I am fairly new here, and to be honest I have no clue if this is the right place to ask. I am currently thinking about replacing a Lightning port with a USB-C port, just for power supply. At first ...
1
vote
0answers
38 views

BJT Amplifier Circuit Analysis Feedback

I've been reading up on small signal analysis to try and better understand audio amplifier circuit design (end goal a discrete BJT guitar amplifier). I'm attempting to apply the knowledge I've picked ...
-2
votes
1answer
39 views

How to detect touch with arduino [closed]

I want to make hexagonal led lights like in this video.These lights touch sensitive. You can turn it on or off by touch to them. I' ll make the body by 3d printer. But I don't know how to detect touch ...
0
votes
1answer
25 views

How does the continuous/peak charge/discharge current change when combining cells with known values in series / parallel arrangements?

Example 16 identical battery cells rated as below: 3.2V 100Ah LiFePO4 Max Continuous Discharge 100A / 1C Max Peak Discharge 200A / 2C for 100s Max Continuous Charge 50A / 0.5C Max Peak Charge 100A / ...

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