Questions tagged [circuits]
Use for questions primarily about circuit design, components, testing or other practical applications.
79
questions
1
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1answer
68 views
BJT Output Characteristics Question
Ok, so I am pretty confused at the moment with a question that I have been given to work out by my lecturer and was wondering if I could get some guidance with it. I will attach images of the question ...
1
vote
0answers
18 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 ...
0
votes
1answer
16 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 ...
0
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0answers
12 views
Thermoelectric cooler parasitics
So I'm looking at performance curves for thermoelectric coolers, and it seems like these curves are so misleading as to be useless unless I'm missing something fundamental.
Suppose I have a ...
-1
votes
1answer
26 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 ...
peterh - Reinstate Monica
2,2864 gold badges22 silver badges42 bronze badges
5
votes
1answer
389 views
I want to understand this pneumatic circuit
I have trouble understanding the following pneumatic circuit diagram:
I am new to reading circuit diagrams and i am unfamiliar with some of the symbols. I would appreciate if somebody could explain ...
0
votes
1answer
24 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 ...
0
votes
1answer
30 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 ...
2
votes
1answer
677 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.
1
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1answer
40 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 ...
0
votes
0answers
22 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.
0
votes
0answers
30 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.
...
1
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2answers
107 views
Designing a loaded voltage divider?
I was wondering how to design this circuit in depth, since I have no idea what to do.
0
votes
1answer
88 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 ...
Mahendra Gunawardena
6,8135 gold badges23 silver badges60 bronze badges
1
vote
0answers
37 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 ...
0
votes
0answers
37 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 ...
1
vote
1answer
63 views
How to choose type of output from a water level switch?
I need to buy a level switch for a quench tower water drainage system. I intend to use its output directly to open a solenoid valve to drain the tank when the switch detects water and close it ...
3
votes
1answer
74 views
Replacement components?
I'm building a tracker for a high altitude balloon but some of the components are out of stock and may not be in before our launch date. I'm good with an iron but have limited engineering knowledge. ...
2
votes
1answer
102 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 ...
1
vote
1answer
17 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 ...
0
votes
1answer
46 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 ...
1
vote
1answer
77 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 ...
1
vote
2answers
41 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 ...
0
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0answers
38 views
Is my understanding of the roles of transistors in this circuit correct?
THE CIRCUIT'S FUNCTIONING
This circuit is a rain water sensor circuit that buzzes when there's water on a probe.I found it on net.1
CIRCUIT COMPONENTS
3 Volts Battery
BC 558 Transistor(PNP)
BC 548 ...
0
votes
1answer
42 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, ...
-1
votes
2answers
61 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 ...
2
votes
0answers
25 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 ...
-1
votes
1answer
55 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 ...
1
vote
1answer
37 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 ...
0
votes
1answer
97 views
What signals are expected on the connectors for this 12V Volkswagen Scirroco wiper motor circuit
EDIT: added a picture of a very similar unit.
I picked up a used VW rear? wiper motor that I want to use for a simple motion experiment.
Having no idea how to power the thing I popped open the case ...
Mahendra Gunawardena
6,8135 gold badges23 silver badges60 bronze badges
2
votes
1answer
188 views
How can I calculate overcurrent from over voltage for the AP9101C IC
I designed a battery charging, protection, and boost circuit for a project I am working on. However, I made a complete noob mistake and forgot to find the overcurrent value for the battery protection ...
1
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2answers
240 views
I am trying to create an op amp based negative voltage regulator
I am trying to find simulate an op amp based linear regulator negative voltage regulator circuit.
I have done the circuit for positive voltages, but does not know how to do it for negative voltage. ...
-1
votes
4answers
163 views
How do you create a negative and positive voltage(-6V and 6V) with a singular voltage source?
I'm trying to use a battery to activate an op amp schmitt trigger but learned that there needs to be both a positive and negative voltage supplied to Vcc+ and Vcc-. I've seen a lot of schematics ...
8
votes
2answers
655 views
What does a Sad Face on a circuit board mean?
I have a Fisher and Paykel Washing Machine (model number WL80T65C, well past warranty) which got rained on (a lot) and one of the capacitors blew up. I've done an amateur replacement of the capacitor ...
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votes
5answers
3k views
Which is the branch of engineering that deals with making gadgets?
Background
I am currently preparing for Entrance Examination for Engineering college , somehow I noticed that I don't even know which branch I want to take and what is the kind of Education I am ...
1
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0answers
18 views
Calculating the water pressure knowing the circuit that tracks it
I'm not very good at physics, but I've got a problem that I really need to solve.
On the second picture you can see a pipe with flowing water. The point of this mechanism is to lit a LED whenever the ...
0
votes
2answers
38 views
Voltage at node A respective to the ground
I want to calculate the voltage at node $A$ respective to the ground.
$R_1=1.8\text{k}\Omega, R_2=3.8\text{k}\Omega, R_3=1.8\text{k}\Omega, R_4=5.8\text{k}\Omega, R_5=2.4\text{k}\Omega$ and $V1=4.3V, ...
0
votes
1answer
54 views
Circuit analysis, voltage in and voltage out
I want to solve $V_o$ in terms of $V_i$ from the following circuit.
$R_1=95.7 \Omega, R_2=9.1 k\Omega, R_3=1.0 M\Omega$
So the solution is form $V_o=kV_i$ and I want the factor k.
I know that:...
0
votes
1answer
40 views
Cannot understand an equation related to impedance. (Power system analysis)
Can someone explain how can we find |Z| term and also from where does the cosine term arrive at the final equation.
0
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0answers
26 views
Confusion about 2-bit adders
I am a little confused about how a 2-bit adder works. For 1-bit adder, my understanding of it is fine and I am able to draw out the truth table for it. However, if lets say I have a 2-bit adder, I can'...
Mahendra Gunawardena
6,8135 gold badges23 silver badges60 bronze badges
3
votes
1answer
269 views
Thevenin equivalent impedance in laplace domain
I can't understand why $Z_{th}$ doesn't include $3\ \Omega$ resistance.
3
votes
1answer
38 views
What's the most practical way to measure angular velocity for small rotations?
I'm looking to measure the angular velocity of an arm as it moves. It seems to be a difficult thing to research, since the term 'angular velocity/frequency' is usually reserved for other areas of ...
1
vote
1answer
56 views
My output is much lower than I expect it to be for my transistor-zener diode voltage regulator
I have created this simulation ( see below) of a transistor and zener diode voltage regulator. The output is supposed to be a steady 5 V. But it is like the top bit s cut, to an approx 4.4 V value, ...
4
votes
1answer
78 views
How do I calculate voltage at an LED in parallel?
I have this circuit:
If D2 was a resistance, I could just combine it with R2 to get some composite resistance that I could put in series with R1. That way, I could calculate the resistance of the ...
Mahendra Gunawardena
6,8135 gold badges23 silver badges60 bronze badges
1
vote
0answers
37 views
How to prototype this circuit using an Arduino and breadboard?
I'm trying to build this circuit for a force transducer such that the data is logged by an Arduino Uno. I have the op-amp recommended in the schematic, but I haven't been able to get stable readings ...
0
votes
1answer
37 views
Voltage controlled switch?
So I am in the process of working on a rather strange and specific project. I am looking to capture as much energy as possible from a small steam turbine using a DC motor and then use that to power ...
0
votes
1answer
33 views
Unbalance voltage mesurements from 63 kV power transformer
After testing a power transformer(pt) and closing its wiring terminals I've encountered that phase S 63 kV correct voltage and phases R and T shows incorrect voltage 32 kV.
Can any body tell why?
0
votes
1answer
190 views
Utilize multiple vehicle power outlets to increase wattage capacity of inverter
I'm trying to determine whether it would be possible to use multiple power outlets in vehicle to increase the wattage that can be obtained.
This question is driven from a desire to install an DC to ...
1
vote
0answers
70 views
Mosfet switching circuit
I am trying to make a MOSFET switching circuit where its gate input is 12V clock pulse. Now when I put the load between (Vdd) and (Drain), there is no drop voltage VDS, but when the gate input falls ...
4
votes
1answer
158 views
Simultaneously charging and transmitting data to an android phone using usb
Dear engineers,
I have to make an engineering project which is a portable solar phone charger. One thing I need to do in it is to somehow charge the phone (android) from the battery (which is charged ...
