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Questions tagged [circuits]

Use for questions primarily about circuit design, components, testing or other practical applications.

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Unable to calculate Thevenin resistance and Norton's current

I have to solve for the Thevenin voltage, Thevenin Resistance and Norton's current for the two following questions. For question C, I am able to calculate the Thevenin Voltage and Norton's current, ...
Nathan Johnson's user avatar
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2 answers
56 views

Alternatives to ceramic PCB

I am looking for a way to create prototype high temperature circuits capable of going up to 500 °C. I know one way is to generate the CAD file and send it to a PCB manufacturer. Another way is to get ...
user1402154's user avatar
1 vote
0 answers
17 views

Failed in upload firmware to esp32

I'm having an issue when uploading code to my ESP32. Previously, I had configured the partition scheme to 'minimal,' and I was able to upload code without any problems. However, after I fixed my ...
Tân Nguyễn Minh's user avatar
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0 answers
24 views

CMOS AC-to-DC Converter Design

I am trying to analytically model the power conversion efficiency of an AC-to-DC power converter circuit (see Figure 1). In this design, the drain-source voltage of each MOS device can be expressed as ...
PikaPika's user avatar
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1 answer
42 views

Converting RMS to Maximum Power

If I have a sinusoidal voltage signal of amplitude $V_m$ driving a resistance $R$, what is the relationship between the RMS power $P_{rms}$ and the maximum power $P_{max}$ delivered to the resistance? ...
PikaPika's user avatar
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55 views

Strange problem with Impedance?

I've encountered a strange problem with a 12V key-fob device. We use a device to remote control a relay via a key-fob transmitter. It's installed in a plastic box that is mounted at an operator ...
Daniel Szalay's user avatar
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1 answer
70 views

What causes a correctly sized circuit breaker to trip?

I have a suicide shower head and even though the breaker is correctly sized it trips after about 6-8 minutes of showering.
Osvaldo Silva's user avatar
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1 answer
54 views

Residential 120V AC vs 12V DC

Can I repurpose residential LED lights (slim, 120V recessed) for my RV by directly providing them with 12V DC power, or is a more accurate approach required to bypass the existing circuit board?
Jfw's user avatar
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-1 votes
1 answer
128 views

Solving a common emitter amplifier problem

My work is posted along with the question. I received help in office hours and this small signal equivalent was derived. I was told to use the formulas in the pictures to derive the voltage gain and ...
School's user avatar
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0 answers
22 views

Self bias FET circuit

I am trying to follow the book’s steps, but I cannot get the same quadratic they did to solve for Vgs. Where is my mistake?
School's user avatar
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0 answers
36 views

Peculiar step-down transformer behavior

I have wired several loaded transformers and when calculating power on H vs X side by multiplying current times voltage the wattage is not even close to equal with the H side having 2 to 3 times more ...
ZipStein's user avatar
-1 votes
1 answer
51 views

Can a 0.5 W resistor be substituted for a 10 W resistor?

Can a 2 kΩ, 0.5 W resistor be substituted for a 2 kΩ, 10 W resistor? Also, what kind of defects would occur?
Fukuo_ka's user avatar
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How do I draw a circuit for a conducting loop inside a solenoid?

To solve a homework problem, I need to redraw the following diagram in circuit form. The large blue circle represents the solenoid. Inside the solenoid, the two gray semicircles represent a wire loop,...
elvishpotato's user avatar
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1 answer
187 views

Mackie CR3 bookshelf speakers only play incredibly quietly on max volume

I've got a set of Mackie CR3s which the company sent to me when I warrantied my purchased set whose L/R selector corroded (was able to save that set by removing the component and hard-wiring). The set ...
Kevbot's user avatar
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1 answer
178 views

Inductor Voltage at t=0

In the circuit below, the switch has been in position 1 indefinitely long and suddenly switches to position 2 at t=0. I'm asked to find the initial voltage of the inductor at t=0. My professor lists ...
James's user avatar
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Reading in voltages using RS485

I have a breadboard with two RS485 modules hooked up, an Arduino Uno R3 and a Raspberry Pi 3 module. We are trying to read in voltages from the RS485 but we are unsure of how to do that using the ...
overlord12's user avatar
2 votes
2 answers
58 views

What is the purpose of the resistor in this circuit

I am trying to convert an AC input into DC output using Diodes, and I found the following diagram for the circuit: I understand the diagram, but I don't fully get why the resistor has to be there, ...
Tim Weigman's user avatar
0 votes
1 answer
34 views

Deviation management - best practice for direct substitutes

It is common practice when building PCBAs to substitute common passive and discrete components, such as caps and resistors, with alternate parts that have the same or better specifications. This is ...
rothloup's user avatar
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Simulinks modeling of 2-loop circuit containing LRC elements

I have been attempting to model the following circuit using KVL and Simulinks: Applying KVL generated these coupled differential equations: $$ 0 = -V + \frac{q_1}{c_1} + R ( \frac{dq_1}{dt} - \frac{...
FawltyPlay's user avatar
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1 answer
952 views

Line to neutral voltage in three-phase power systems

I have the book "Power system analysis and design" by Sarma. In his intro to balanced LN voltages, in chapter 2 p62 he states: $$V_{LL} = \sqrt{3} V_{LN} \angle30º$$ but later in the chapter,...
RMS's user avatar
  • 275
-1 votes
2 answers
327 views

Calculate voltage across LED

For this circuit, how to calculate the voltage across the LED when the potentiometer is turned please? Is there a formula for this please? Battery: 6 V, Resistor: 200 ohms, Potentiometer: 250 ohm How ...
Electric's user avatar
0 votes
3 answers
206 views

Magnetising a needle with static electricity using silk cloth

A nautical navigation textbook on my table says that we can magnetise a non-magnetised needle by rubbing it with a silk cloth. I decided to cross check on the internet, and found some experts calling ...
El Flea's user avatar
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40 views

Circuit analysis

enter image description here I don’t understand what is the Use of ‘Vin’ as its anode connects to the open circuit.So I can’t even solve QA
user34891's user avatar
0 votes
2 answers
148 views

Circuit with Contradiction

What would happen in real life if you made a paradoxical circuit (a circuit whose output is on iff its output is off). Something like this: Would the discrete model break down and the output end up ...
Sam Donovan's user avatar
1 vote
0 answers
321 views

Charging a 2020 M1 Macbook Pro from a low-voltage solar array

I'm working on a small project to mount solar panels to a Macbook case which would allow it to charge/offset battery consumption. I noticed that I was able to power the Macbook on public transport ...
IslaStewart's user avatar
1 vote
1 answer
31 views

Why wouldn't grounding before a load in DC circuitry affect it? [duplicate]

Considering that the ground is a a real and connected to earth ground, if the electrons have a low resistance path to it from the negative pole, why would the circuity still work? Maybe you could ...
HighlightXII's user avatar
1 vote
1 answer
157 views

Electrical potential and grounding in a circuity, why it works?

I thought I understood the ground concept but now I'm a lot confused. From: Pg.67 Practical Electronics for Inventors - Scherz Paul As it's explained in the book, the first circuity is the one that's ...
HighlightXII's user avatar
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0 answers
18 views

Building drone transceiver module with 2 recievers onboard to switch gates ON/OFF to turn motors On/Off

I'm looking for any resource that can help me build a radio (no infrared) controlled circuit with two receivers onboard a drone. The purpose of this circuit is for research and education. Whenever ...
Digvijay's user avatar
2 votes
0 answers
99 views

Transferring the project from "Altium Design" to "SolidWorks" while maintaining silk-screen printing, sizes and everything else

I want to transfer the PCB project to solidwork from altium design, I read forums on how to do it better, and so: Save to STEP. The option is good and working, but I did not like the option, since ...
Антон's user avatar
0 votes
1 answer
69 views

How to make a wireless modem using a normal Wi-Fi router and a 4g usb modem

I have a normal TP link (Model: TL-WR841N) router and an USB 4g modem. But the WIFI router does not have any USB port. I want to connect the USB modem with the router, want to share internet ...
Shakib's user avatar
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0 votes
1 answer
42 views

Explanation for photovoltaic circuit

My background is in Environmental Science, although I have recently been taught in the basics for energy engineering especially for solar panels. I'm currently using PVsyst to build solar panels on a ...
Lime's user avatar
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1 answer
61 views

Phasor representation of RC circuit

I am struggling to understand how to take the KCL equation from time domain to Phasor domain. The time domain KCL equation is easy to understand and represented here: The phasor domain equation looks ...
natebcx's user avatar
2 votes
1 answer
706 views

Unknown circuit component with glass encapsulated contacts

This is an unsoldered circuit component that had two metal pieces that weren't making contact inside a thin glass tube. What is this? I haven't seen anything like it before.
Steve's user avatar
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0 answers
32 views

RLC circuit problem

After the switch is open for a long time, it is closed at t = 0. How can I find iL(t) and Vc(t) for t>=0? I tried step response for RLC circuit but I could not apply.
Can's user avatar
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-1 votes
1 answer
53 views

How can I create an RL circuit?

I want to create a RL circuit that has a dc voltage source, lamp, switch, R and L elements are connected in series. How can I design the circuit so that the lamp flashes from the moment the switch is ...
Can's user avatar
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1 vote
1 answer
550 views

Circuit to provide position control for double action hydraulic actuator

I was wondering how to construct a hydraulic circuit to control a hydraulic double acting piston/actuator enabling the electronic control of the piston extension. I have found the following pneumatic ...
user19440's user avatar
  • 113
0 votes
0 answers
35 views

IP grade for specific plastic case

I´m designing an access control device and I need to place it in a plastic case so it can be easily installed on a wall, for example. Also, the PCB will have a special coating for humidity protection. ...
LazyTurtle's user avatar
0 votes
1 answer
1k views

Simulation of RC circuit using Proteus

I am learning how to use Proteus and I have come across the charging and discharging of a capacitor problem. My main problem is on how to use the graph feature of Proteus to simulate how the voltage ...
Fil's user avatar
  • 123
2 votes
0 answers
57 views

Overcurrent protection, limit for nominal current or stall?

Background: I'm currently working on a robotics design that will drill through soil. I have selected a 48V motor who's nominal current is 3.17A and has a stall current of 42A. I will be driving the ...
gunter's user avatar
  • 321
0 votes
0 answers
42 views

E-Lock Circuit Help

For school I was assigned a madlab circuit, E-lock, to build and explain how it works, and to be frank, I have no clue how it works. I was able to build it and it functions as it is suppose to: using ...
Scott Scott's user avatar
1 vote
1 answer
83 views

Thermal Capacitance - Convention for Modeling of Electrical Equivalent

As an EE, I am very comfortable with the mapping of thermal quantities to their electrical equivalents. However, understanding how thermal capacitances should be connected is driving me crazy. this ...
banjoeschmoe's user avatar
1 vote
1 answer
302 views

How can I get final value of $V_{out}$ at $t=∞$ in RC circuit?

I can obtain the transfer function in this RC circuit. $$ \frac{V_{out}}{V_{in}} = \frac{1}{(RCs+1)} $$ When $V_{in}$ is set to $10V$, how can I get final value of $V_{out}$ at $t=∞$? I tried to use ...
hihello's user avatar
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0 votes
1 answer
70 views

How do I reduce the mains spike in a switched mode PSU?

I have a switched-mode PSU for a gaming laptop. It has a bad habit of burning out the switches on mains extension panels when I turn it on (two in the last four days). The turn-on surge is always ...
riemannzz's user avatar
  • 101
0 votes
1 answer
385 views

Why is the gain of an op-amp 0 when it is saturated?

My initial question got raised after a statement I read in a book under negative feedback - “It is assumed that the op-amp is not saturated”. I wanted to know why. According to my consequent research, ...
Richie Harvy's user avatar
2 votes
2 answers
213 views

Is it possible to build a DIY RLC circuit for a classroom demonstration?

I was describing the mathematics of RLC circuits to my students, and was wondering if it's possible to build an actual RLC circuit with coils of wire and an inductor and a variable capacitor. The ...
user128063's user avatar
-1 votes
2 answers
115 views

Clarification on how current flows from a socket into a device

I'm trying to understand a bit about electrical circuits. I've understood the basic equations like V = IR. They are a few things I'm confused about. My understanding is that when you have a circuit ...
BMan98's user avatar
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2 votes
0 answers
40 views

Electrical component most likely to fail in window AC unit after power surge?

I have a window AC unit, 115 VAC, 10 amps. Power went out earlier in the week due to the big storm on the east coast and once it came back on every LED on the control panel was lit (not typical) and ...
jko's user avatar
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-1 votes
1 answer
144 views

Help in Inverse Laplace Transform in Circuit Analysis

Inverse Laplace Transform $\frac{1}{s^2 + \sqrt{2}s + 1}$ so what I did it changed the denominator to complete the square format which is (s+$\frac{\sqrt{2}}{2})^2$ + $\frac{1}{2}$ , then I can solve ...
EM4's user avatar
  • 99
1 vote
1 answer
48 views

Switching a Circuit on-and-off In-step with the Rotation of a Drive-shaft (Mechanically)

I'm working on a project. The Salient part here is a drive-shaft connected to a bearing, onto which a simple circuit is mounted. I want to switch the circuit on every $π$ and off for the other $π$ of ...
EEEEsl's user avatar
  • 11
2 votes
1 answer
356 views

Can I connect a power supply main (SPH) and inverter main (SPH) with common neutral to a TP MCB?

I have limited knowledge of MCBs and just doing research to secure my kitchen. I want to connect my power supply main and inverter main with common neutral to a TP MCB. This MCB will be placed in the ...
Abhay Kumar's user avatar