Questions tagged [circuit-analysis]
Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network. Consider using in conjunction with tags for the particular analysis technique(s) in question: "nodal-analysis", "mesh-analysis", "superposition", etc.
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How do I use superposition to solve a circuit?
Yes, this is a pedagogical question. While answering another recent question, I wanted to refer the OP to concise instructions for using superposition to solve circuits. I found that all the easily ...
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Diode Circuit Analysis Conflicts
I am very confused about how to analyze diode circuits.
I have read sources that claim the voltage drop across the diode to be 0.5-0.7 V but this seems to be inconsistent with what happens when ...
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Logic level converter using Transistors
I am trying to make a logic level converter using transistor BC547.
This is to convert Voltage level of Rpi Gpio from 3.3 to 5V.
I have wired the circuit according to this diagram:
I have done this ...
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Why is the voltage of a capacitor equal to the voltage of a battery connected it?
I am confused by this question.
If we connect a resistor in series to capacitor then the voltage will drop across the resistor and now voltage across the capacitor is less than the source, then why ...
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How do you determine the effective resistance of a finite grid of resistors?
Disclaimer: I am a geophysicist with limited electrical engineering background. I am not sure if this problem is incredibly easy, incredibly complex, or completely nonsensical.
My goal: Determine the ...
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Is this an astable multivibrator?
In this circuit the LED flashes on and off, however could it be classified as an astable multivibrator?
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How to know if this is a band-pass filter?
I have the circuit below. How can I see that it is a band-pass filter?
I tried calculating the equivalent impedance for the parallel part of the circuit:
$$\bar{Z}_{parallel} = \frac{\bar{Z}_C\bar{Z}...
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Calculation of output impedance of CE emitter bias configuration( unbypassed) with r_0
Can anyone please help me with finding the output impedance of the circuit.? I tried but can't find the answer
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How does the tester screwdriver work?
How does the tester screwdriver work? If I put the tester screwdriver inside the "hot wire" of an electrical socket, it lits up if I press my finger against the metal cap on top of the screwdriver. ...
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Meaning of Sigma in Laplace transform
I found the question below in a forum and I also have same problem. Unfortunately, there is no answer at all so I will post it here hope someone could make it clear.
A gain relation in a circuit of ...
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Can two voltmeters connected to the same terminals show different values? Circuit with induced EMF
The circuit shown below consists of two resistors connected in series that form a closed loop. No electrical sources are in that loop.Let’s assume that the resistance of the wires that connect the ...
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Help understanding how op amps work
I've just been introduced to op-amps and am having a little trouble understanding exactly how they work. Take this circuit, for example.
Suppose that there's a 1V source here. Without the op amp ...
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How does early voltage affect collector current?
The transistor in the following circuit is said to feature \$I_{C} = 1.0mA\$ at \$V_{BE} = 0.7V\$ and \$V_{CE} = 10V\$. If \$V_{A} = 50V\$ and \$\beta = 50\$, find \$V_{B}\$ and \$V_{C}\$.
simulate ...
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Does the resistor have to be before or after the component [duplicate]
I am an electronics beginner and I created a small little circuit, just a battery a resistor and a led, then to ground. This is the circuit:
simulate this circuit – Schematic created using ...
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Op-amp with T network in the feedback path
How do I calculate the equivalent T network resistance of the inverting amplifier below? The answer is 10 MΩ, but I don't know how to calculate it. I'm not looking for just a formula, but an in-depth ...
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Understanding this AC coupled circuit
I'm having a little trouble understanding this circuit and could use some help.
So far I understand that this is an AC coupled circuit, and the capacitor is a blocking capacitor. I also know that ...
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Why is D2 switched off and T4 not in saturation mode in 7408 TTL Gate as shown below?
In the circuit, when both the inputs are high at 5V, than why is D2 switched off? Will it not draw voltage from Vcc?
Also, when one of the input is low, why is T4 not running in saturation mode? Will ...
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Differential stage Av value with current sources
Why all books told that Av differential of an differential input stage in power amp is very big? Ad = Rc/re, but if there are current sources in the emitter and collector circuit they will have too ...
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STM32 Understanding GPIO Settings
In STM32 Standard Peripheral library, we need to configure the GPIO.
But there are 3 functions which I not sure how to configure them;
GPIO_InitStructure.GPIO_Speed
GPIO_InitStructure.GPIO_OType
...
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Do electrons actually flow when a voltage is applied?
It's said in books that a circuit is a closed path and thus that electrons come back to the source. If that's the case, what would happen when there were an earth fault in a circuit? How would the ...
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How to interpret Vgs(th) min/max in a MOSFET datasheet?
This is a screenshot of IRF9640 MOSFET datasheet. Will you please tell me, what is meant by max and min value of Vgs threshold voltage. Also what they mean by test condition.
Whether the max and min ...
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Short circuit = zero voltage?
Reading this question and its answers (as well as other questions), it seems that in an idealized short-circuit with zero resistance, one concludes the voltage is zero.
This seems completely wrong.
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Self Checking Circuit
I was reading the specs. of an electronic module used in process-safety applications & came across this note:
Self-Checking (Circuitry): a circuit with the capability to
electronically verify ...
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Arriving at a wrong output impedance for a BJT Emitter Follower Configuration Circuit
We've to calculate output impedance of the circuit (figure 1). Although i understood the textbook solution (figure 2, figure 3), I took a different approach and arrived at a wrong answer.
step 1: I ...
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Why can current only flow in loops? [duplicate]
In the following image:
Why can't current flow across the following wire?
It's a simple question, but I've kind off always wondered.
Thanks!
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How to choose resistor values in op-amps
Ok so my question is what resistor values should I choose for this amplifier. Vin is 0.5Vpp, 50kHz and the desired Vout is 25Vpp, so the overall voltage gain is 50. I know that the voltage gain for an ...
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Operation of tuned collector feedback oscillator
I am trying to understand the following tuned collector feedback oscillator extracted from here using LTSpice. I understand that L1 and C1 creates the resonance at the oscillation frequency and L2 ...
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How to solve infinite grid with the observing terminals at diagonal of infinite square matrix?
The answer given is 2/3ohm solution is not given but I can expect how they got that answer but can't justify the way.
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Transient analysis of inductor circuit and back EMF
In a lecture exercise from a circuit course, I encountered the following circuit with only an inductor and a voltage source. The \$v\$ vs \$t\$ and \$i\$ vs \$t\$ graph is as follows:
-The KVL ...
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How do Circuit Simulators actually work?
I recently had the opportunity to play around with LiveWire, which is a circuit simulator and began wondering how exactly they computed the voltages across each component and the current going through ...
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What are the various 'properties' of a diode?
I have come across various properties of a diode, phrased differently in different places (product sheet, everycircuit, etc.). For example:
The wavelength is the simplest and that is the color of ...
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Why, in a passive circuit with a sinusoidal input, do all voltages and currents have the same sinusoidal behavior as the input?
I am familiar that in any circuit composed of linear passive elements and a sinusoidal input, all voltages and currents through and across any element will exhibit the same sinusoidal behavior and ...
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Superposition principle: Dependent sources treated as independent sources
Since I began studying, I was taught that when analysing a circuit using multiple sources, independent sources could be turned off, meaning that I could transform a voltage source into a short, and a ...
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What is AC actually?
What is actually alternating current (AC)? And direct current (DC)? I've been reading several books about basic electric circuits analysis and they are contradictory.
Some books say that AC is the ...
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Application of Complex Numbers [closed]
I was just wondering how complex numbers can be applied in electrical engineering and why we use complex numbers over regular, real numbers for this application (e.g what capabilities does the complex ...
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Why doesn't current flow through the common part of a circuit?
I'm reading a book on computing that has a couple of introductory chapters on electronics. The author imagines a situation in which you and your next door neighbor set up a bidirectional telegraph to ...
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Loading effect of two stages of RC filter
The mathematics result does not match with simulator results.
The transfer function of a first order passive low pass filter is:
$$\frac{V_{out}}{V_{in}} = \frac{1}{(sCR + 1)}$$
If I have two stages ...
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finding the output resistance of bjt folded cascode
I am being asked to find the output resistance of following BJT cascode amplifier, from "Microelectronic Circuits" by Sedra and Smith, 7th edition, problem 8.80.a on page 588.
Now I decided to ...
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Help dimensioning resistors in a two NPN transistor current limiter circuit
I'm trying to design the current limiter circuit shown above which I saw on this website:
http://electronicdesign.com/power/current-limiter-offers-circuit-protection-low-voltage-drop
I'm using 18V - ...
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Norton equivalent with a single voltage source
I'm trying to find the Norton equivalent with respect to the load resistor RL for the DC circuit below.
Each of the resistors have an equal resistance R. Removing the load resistor, I am having a ...
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Algorithm for substituting any resistance network to one resistance
I am wondering what the common approach is to substituting any resistance network to one resistance only given that the a voltage is applied between two random nodes.
For example this network took me ...
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Analysing a circuit to determine what is in series or in parallel
This is probably a very basic question but I have the following circuit, I am not sure what is in series and what is in parallel or if they are all in parallel, initially I thought R2 and R3 were in ...
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How do I derive the transfer function of this circuit in terms of its corner frequencies?
How would I derive the transfer function of this circuit in terms of its corner frequencies?
Edit: The solution I am trying to derive is the following
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Is there current flowing through this blank wire?
simulate this circuit – Schematic created using CircuitLab
Does any current flow from point A to point B?
My guess is no. Because both of those points are connected to a ground symbol by ...
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Biasing in common-emitter amplifier
I'm having trouble understanding the biasing of the common-emitter amplifier as depicted below:
(Image source: Electronics Tutorials - Common Emitter Amplifier)
I keep reading that we should bias ...
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What is a flip flop?
There seem to be a number of different definitions of flip-flops and latches out there, some of which are contradictory.
The Computer Science text book for the course I teach is probably the most ...
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How to calculate for how long an LED emits light when in series with a capacitor?
Given the following DC circuit with a fully discharged capacitor (\$V_c(0) = 0 V\$):
How can I calculate for how long the LED emits light until it "turns off"?
The LED is a red one with a ...
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Does ground pour circumvent bypass capacitors?
I am working on a two-layer PCB with ground pour in both layers. A few of the components recommend using bypass capacitors.
Going off of this guide, I understand that it is important that the current ...
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Why superposition theorem fails here?
I have a simple circuit consisting of 2 ideal voltages sources (each 5V) parallel to a resistor of 5 ohms. The current along the resistor is 1A, right? But by applying the superposition principle (i.e....
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How does this timer circuit work?
I am stumped on how this circuit works. I am quite new to electronics but I know the basics of capacitors, transistors, ohm's law .etc, but I have no clue why when the switch(S1) is switched on the ...
