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Questions tagged [circuits]

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0answers
44 views

Solving a circuit with two power sources and three resistors, trying to find Vout [on hold]

Consider the electric circuit shown in Figure 6. Find the expression for the output voltage Vout as a function of voltages V1 and V2 and resistances R1 and R2. I just am confused about how the ...
0
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1answer
25 views

switching two power sources

I have used the circuit below to switch between two power sources. The purpose was to have a backup power source once the other is switched off by a controller in the system. While testing the ...
0
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1answer
62 views

Limitations of sound card oscilloscope

I’m supposed to build a buffer circuit for pc oscilloscope using the sound card of the pc and a software “zelscope”; however there’re limitations: Not possible to display DC because there’s a DC ...
0
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0answers
50 views

Help with determining the open circuit voltage

Can someone go through why Vxy= -84mV? Given the values off VB=180mv R1=22ohms R2=68ohms R3=150 ohms. Many thanks
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0answers
35 views

Current flow on this branch [duplicate]

What happens in this current branch? In circuit analysis how to deal with branches like this?
1
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1answer
27 views

EAGLE - Singular matrix warning in RL circuit simulation

I'm studying for my electrical circuits exam and since Eagle is used for some future exams I thought I could learn it and double-check my calculations by simulating with Eagle. I'm trying to ...
38
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6answers
8k views

Why does my circuit work on a breadboard, but not on a perfboard? I am new to soldering

I'm a total beginner when it comes to soldering, and recently I've been trying (and failing) to solder together a simple circuit I put together for a Raspberry Pi sensor. Although it works fine on ...
0
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0answers
20 views

Attenuation factor

In A.C. Circuits if R=2k ohm and c=2 micro farad what is the frequency at which the attenuation factor A drops by 20% of its maximum value? In the attached picture my attempted to solve the question . ...
0
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1answer
62 views

Finding resistance of unknown resistors in 2 pairs of parallel circuits

If you are given two pairs of parallel circuits, with three unknown resistors and one 4ohm resistor, with the total resistance totaling 3/4 ohms ; how are you supposed to find the resistance the ...
0
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0answers
29 views

Understanding PMOS's and NMOS's

The problem says solve assuming VI = 0, +2.5V, and -2.5V. I know that if VI = -2.5V the MOSFET's are in cutoff and that VDS = 0. and IDP and IDN will = 0, but would V0 also = 0? If VI = 0 the ...
0
votes
1answer
56 views

I have a 2 A 12 V regulated power supply and I want to use it to emulate a 9 V battery for a breadboard

I have a 2 amp 12 volt regulated power supply and I want to use it to emulate a 9 volt battery for a breadboard. However, I need to protect the power source and the components used in my breadboard ...
1
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2answers
107 views

Different voltage sources in parallel

I realize connecting two different voltage sources in parallel is a contradiction (in an ideal circuit). But if I were to connect this in practice and measure the voltage across points A and B, what ...
3
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2answers
63 views

KVL On A Circuit With 2 Voltage Sources

I want to apply Kirchhoff's Voltage Law on the circuit showed below. When I apply it, I form this equation : $$-20 + Vx - 3Vx - 6i = 0$$ However, my book forms this equation: $$ Vx + 3Vx + 6i - 20 ...
1
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1answer
84 views

Having trouble determining circuit purpose

My apologies if this is the wrong section. I am having trouble trying to determine the purpose of circuit. As in, what would this circuit be useful for, if it was installed in a logic board. The ...
1
vote
1answer
62 views

Is it parallel or series

In the figure below, an RLC circuit, the author in the book says, that the resonant circuit sees Rs and RL to be parallel so he combined them (R total = the parallel sum of Rs and RL), is it right ...
1
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1answer
46 views

Problem with Network Topology based on circuits

I have started reading a book lately which covers an introduction to electric circuits. Currently, I'm trying to learn the basic network topology needed to solve exercises in a more efficient manner. ...
1
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3answers
96 views

7432 behaves like an AND gate & 7408 behaves like an OR gate

Ok. First of all, I'm an absolute beginner about IC and circuits. If you will view the pictures, you will notice that the 7432 behaves like an AND gate and the 7408 behaves like an OR gate. PS. I ...
4
votes
3answers
229 views

Potential difference and current flow

I've been taught that electrons move from cathode to the anode (negative and positive). But what happens when I apply positive voltages at +10V at one end of the circuit and +6V at the other? How ...
-1
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1answer
112 views

Integrate residential hardwired alarm zone with modern wireless sensor

I have an old alarm system in my house that I would like to integrate with a modern system. The old system has hardwired circuits where multiple reed sensors in series monitor a zone with as many ...
0
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2answers
139 views

Raspberry Pi not Compatible with Mosfet?

This is my mosfet datasheet RFP30N06LE i have my schematic setup exactly like this (except powering a 12v load not 60v) and even confirming with a multimeter when i set my gpio pin to high that there ...
1
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1answer
41 views

How do I find the Thevenin voltage and resistance equations of this circuit?

How do I find the Thevenin voltage and resistance equations of this circuit, with respect to the terminals U and G when Rc, Vc, Rt, and Rtrans are given?
0
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1answer
34 views

The differential protection relay

The differential protection relay may lose its stability through fault due to the saturation of a CT magnetic circuit during a short circuit condition. To overcome this, which type of relay should be ...
0
votes
1answer
40 views

Simple Circuit: light source seperated from signal source?

Forgive me for the simple question! How would I create a circuit for a light that is switched on when another light is switched on? Basically I want to use a more powerful source for a new light ...
0
votes
1answer
61 views

Small DC voltage boost without step-up boost circuit?

I have a simple DC circuit (Arduino related) with a USB power supply that's giving me 4.9V. Is there a way, with minimal components and without using an inductor, to boost that voltage to 5.2V? I ...
0
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0answers
36 views

Equivalence between two circuits

the problem I was working asked for the Thevenin equivalent of a circuit, requiring it to be done in two steps and then to "join" the parts together. The top circuit is the one I came up with, but the ...
2
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2answers
149 views

Circuit To Measure Phase difference

Is there any classical analog circuit to measure the phase difference between two analog signals ( especially sinusoidal signals )? I want to measure the phase difference between two sinusoid signals ...
2
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3answers
133 views

Do the resistors affect every component of the circuit?

I've noticed something strange in the circuits schemes I saw in a book. Let's say that there is an LED and it's anode is connected to a 5V power source, and it's cathode is connected to ground. ...
0
votes
2answers
160 views

How does this precision full wave rectifier work?

I am making a VU meter, and I need to rectify the audio signal for the IC comparator chip. I found this circuit in the datasheet, but I am unsure of how it works. I understand that the LF351 op amp ...
1
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1answer
90 views

Stabilizing IR Emitter/Receiver circuits

Need some help making these IR Emitter/Receiver circuits, and their power, more stable. Building a large, 8’ x 10’ LED art installation (in progress details included). LED Butterflies in a grove of ...
1
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1answer
369 views

Fourier Transform vs. Laplace Transform?

The question arose to me earlier, and I never really understood it.. What is the difference between fourier transform and laplace transform in terms of analyzing an overall circuit? I don't quite ...
0
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1answer
43 views

Series/parallel combination of resistance/capacitance in an RC circuit (wrt LCR meter readings)

I have this equivalent circuit I am working on. I have to find out individual values of all components in it. I can measure resistance, capacitance and impedance of the whole circuit. I am not sure ...
1
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0answers
56 views

Superposition theorem for transient analysis

Can we apply superposition theorem in transient analysis of circuits? I don't think it can be used since during transient state the input and output relation is not linear and is rather explained by ...
2
votes
3answers
123 views

AC through inductance only

How will we have a current through a pure inductive coil connected with ac power supply? I am confused because the induced emf will be equal to the applied voltage but opposite in direction, \$emf = -...
1
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1answer
56 views

Trouble analyzing BJT circuits when we change β from very high to 100

For example we have this circuit: Originally we assumed β to be very high and we assume VBE = 0.7. So for this, we have IB = 0 and therefore V1 = -0.7V and V2 = 3.4V. Now that we have β at 100, IV1 ...
0
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2answers
117 views

will the difference between a .001 cap and a .0015 cap matter?

I am doing a build for a guitar stomp box from this website and was wondering if a .0015 capacitor could be used instead of a .001 capacitor. The build i got from https://www.tonefiend.com//wp-content/...
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1answer
94 views

replace ceramic capcacitor with electrolytic one

I need help, that i have a lack of ceramic capacitor value variety in my country. I need 47μF (microfarad) and 2.2μF (microfarad) ceramic capacitor and i can't get these values. So the question is,...
0
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2answers
46 views

Thévenin's theorem exercise, resistances

I've some problem identifying the \$R_{th}\$ simulate this circuit – Schematic created using CircuitLab Removing the load and short circuiting the Voltage source we get : simulate this ...
1
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1answer
66 views

Elements' order in a circuit

I was reading about source transformations and came across an example where there was a change in the order of two series elements, is this always possible? The same for in parallel elements but that ...
0
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1answer
42 views

Where does the indicated negative voltage terminal lie on this circuit?

Does the negative voltage terminal lie after the 150v source ?
2
votes
1answer
291 views

RL circuit: How to determine the equivalent resistance of the circuit?

So I'm working on an RL circuit and the solution is stated to be that R1 and R3 are in series, but I didn't think that was the case because they don't have the same current through them. Given ...
0
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1answer
98 views

Black Box Measure

This black box show in the next figure can be created with logic gates, op amps, PIC, FPGA (Basys 2), nevertheless you can’t use any kind of digital - analog converter, the signal obtained on the ...
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1answer
138 views

I'm confused as to which resistors you include when calculating τ=RC, in an RC circuit?

In example 7.14, how come the Rf resistor is not part of the RC circuit...that is, why don't we need to include Rf when finding the time constant (RC)? [![enter image description here][2]][2]
0
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1answer
34 views

I need help understanding something from a RL circuit problem.

In the below example, why is the voltage source shorted for t>0, and why does it say "the 6-ohm resistor is shorted" in the paragraph about t<0? Isnt it open circuit there?
0
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2answers
99 views

What resistor to choose for circuit? [duplicate]

I'm not good at physics, but I'm trying to make a lantern. So I have an LED with this characteristics: N = 3 Watt I = 0.7 Ampere U = 3.4-3.6 Volt So I connect it to 6V battery, but need ~3.5 V. ...
0
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2answers
84 views

What is the impedance in a theoretical LC circuit?

While writing a paper about an experiment I am conducting, I was wondering how inductor-capacitor circuits theoretically behaved. In theory, we assume that wires and components that are not resistors ...
1
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2answers
94 views

Network Theorems on DC and AC

Are network theorems (KVL, KCL, Thevenin, Norton, Superposition, Max Power Transfer) applicable on both DC and AC networks
1
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3answers
165 views

How to find current in this circuit passing through 4ohm resistor

Below I have added my solution after the question so please let me know how I can solve it after the last step: These steps to follow to solve the question from where i left in my post , FYI :As ...
0
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3answers
179 views

Keep a circuit closed after activating a reed switch NO (normally open)

I need a circuit that it is open until I bring near a magnet that closes a NO reed switch for a short interval of time. I need the circuit keep closed for ever. Thanks!
0
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2answers
40 views

Circuit analysis with node voltage method

The problem requires I determine the value of I0, I think my solution is correct but I don't know how to check because I got the problem from a text with no answers. Looking for more experienced eyes ...
1
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1answer
1k views

How do I implement a sequence generator using a universal shift register?

How can I implement a sequence generator that generates the following sequence 0000 1000 0001 0011 0110 1101 1110 1111 using a universal shift register? The shift register I need to use is the 74LS194 ...