Questions tagged [circuit-analysis]
Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network.
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Why does KCL not work for this node?
Why does KCL not work at this node?
From the DC operating point you can see that:
IR2 + IL1 ≈ 1mA + 2.45uA is not equal to ID1 + IB1 ≈ 0.16mA + 8nA.
So where does ...
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Tellegen's Theorem Question
In Irwin's textbook on Basic Circuit Analysis, there is the following exercise:
Up to this point in the book, the concepts of dependent and independent sources have been discussed, and also the ...
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Why does adding a resistance in parallel decreases the circuit total resistance? [closed]
Why does adding a resistance in parallel decreases the circuit total resistance?
Before you close the questions a duplicate, please read further: I know the classic explanation for this, and I think ...
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Crystal oscillator error due to ppm
In this link, the accepted answer states that there may be an error of 1 minute per month if the crystal ppm is 20ppm.
Can someone help me with the math of how the error of 1 minute is arrived?
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Is this circuit a series or parallel combination?
I’ve been confused on this aspect of my textbook. To me it appears that the answer is that it is both a series and parallel combination of elements, but I’m not sure if that is possible. Thank you.
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What energy is produced in cable connecting the two terrestrial magnetic poles following this discovery of a variable magnetic field around the earth? [closed]
Principle of operation with scientific sources:
Earth's interior is a far from quiet place. Deep below our surface
activities, the planet rumbles with activity, from plate tectonics to
convection ...
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How to find Thevenin's Equivalent Resistance
I am asked to find the thevenin equivalent of this circuit but I am having trouble. The solution says that:
Rth=2(RxRy)/(Rx+Ry)
Vth= (VxRy+VyRx)/(Rx+Ry)
Can someone please explain to me how to arrive ...
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RC 90 deg phase shift
What does 90 deg phase shift actually mean?
Like, consider this below RC circuit.
simulate this circuit – Schematic created using CircuitLab
From what I understand, when I apply a sine wave at ...
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Using Power to Determine if Circuit Components are Compatible
When I am designing circuits, I usually look at the current and voltage specs of my source to determine if my source is sufficient for my circuit. For example, if I have a load that requires 500mA of ...
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Level shift input -1V/+1V to 0V/+3V [closed]
I need to level shift an Arduino input from -1V/+1V to 0V/+3V.
Can anybody please help?
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Why are these capacitors treated as if they are in series? Why must the incoming and outgoing current in a battery always be equal?
A circuit with three capacitors and an open end at A:
I am a high school student. I am very confused by this example.
The circuit is open at end "A" as shown but still there would be some ...
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Distortion pedal volume and tone control messing up circuit
I have built a distortion pedal with 3 variable controls: gain, tone and volume. R8 is my gain control (it will be a potentiometer with 50k to 500k resistance.) R5 is the tone control, (low pass ...
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Using complex impedance
Any help getting the answer shown here?
I have tried adding the complex impedance of L and R in series and then adding that to C in parallel. I'm not super sure about that last step, and then ...
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Active inductor
I am designing active inductor using OTAs (Transconductance amplifiers) and have a problem writing an equations.
I wrote two equations for nodes V2+ and V2- and input current Iin.
$$ 0=sCV^+_{2}+g_1(...
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Grounding sensors to large bodies
I've attached a diagram of what I'm talking about.
I have a large (600x300x10 mm) aluminum block in which I place thermistors to monitor the temperature distribution in the plate (in a standard ...
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With given impedance matching network, how to find the possible matchable load impedance range
I have some questions regarding this schematic using Keysight ADS here. The matching network is intended to function at 13.56MHz. The shunt capacitor has a range of 150-1500pF capacitance and the ...
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Maximum current going through a solenoid
L1 and R3 represent a solenoid in the schematic below. In my textbook, it's mentioned that the maximum current through the solenoid can be approximated as the voltage supply (Vcc) divided by the value ...
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How many loads can I have on an open drain output?
So I am using this AND gate which has an open drain output. I am trying to determine how many loads that I can place on this output.
I see in the datasheet, that the Iol is over 1mA, but I am unsure ...
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Thevenin's theorem for Voltage divider bias
I am calculating the base current of transistor Q1. To simplify the circuit equations, I applied the Thevenin's theorem and converter V1 and R1, R2 into Vth and Rth as shown in the image.
Vth= V1x(R2/...
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Confusion In RC circuit
I want to calculate voltage across the resistor.
I divided the circuit into two parts:
Charging=0<t<1, 2<t<3, 5<t<6(ms)...
Discharging=1<t<2,4<t<5,7<t<8(ms)...
$$...
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Op-amp exercise [closed]
R1 = 6,8kohm R5 = 470ohm R10 = 1,8kohm
Hello, I'm having trouble to find the gain of this circuit. I know that U1 and U2 act as buffers and the output from both op-amps are vid. I've tried to find the ...
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How would I get the solution for this question? [closed]
The 10kHz frequency mentioned in the question was wrong and was meant to be in rad/s. The resulting capacitor value is supposed to be 464 but I can't seem to get this answer, I know we need to use kf ...
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Series and Parallel Capacitors in Circuit Analysis
In the circuit below:
I performed my calculations considering:
$$\frac1{C_{eq}}=\sum_{k=1}^N C_k^{-1},$$
and
$$C_{eq}=\sum_{k=1}^N C_k,$$
when the capacitors are in series and when they are in ...
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Base resistor too low problematic?
I have recently designed and ordered some PCBs which can combine a horizontal and a vertical video sync signal into one composite sync signal (all are TTL signals). This is done using a BJT circuit ...
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How would you find the impedance of this circuit? [closed]
I am working on a project using C++ to find the impedance of a circuit. In implementing the program I have realised that the program cannot find the impedance for a circuit of this type.
My intuitive ...
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How to derive effective transconductance versus oscillation amplitude in a oscillator?
In the page below in the lecture note shows a plot of effective transconductance versus oscillation amplitude.
How is it derived? Or is there any source to derive effective transconductance versus ...
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Distortion Pedal Design
I am building a guitar pedal and came across a reference design here: https://www.wamplerpedals.com/blog/uncategorized/2020/05/how-to-design-a-basic-overdrive-pedal-circuit/
I'm not sure why the ...
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How do I find the gain function for this circuit?
The cicuit shows a high order low pass filter, where the voltage is 240V RMS. I was told to use laplace to find v0/vi but i am still confused on how to get this and solve for the circuit as asked. I ...
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Peak current of inrush limiting inductor?
I have this tricky question and I can't wrap my head around it.
There is this inductor to limit the inrush current that will be charging up a capacitor. I'm questioning the design of it, but I don't ...
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Can this circuit with two resistors oscillate?
From this lecture note.
Can this circuit oscillate as what the lecture said?
I did simulate this circuit in LTspice but it doesn't work.
The step from 1V to 0V does have many frequency components ...
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How to find noise sources from noise figure data?
An amplifier datasheet provides noise measurements that show it has a noise figure of 3dB for R_s = 100Ω and R_s = 10kΩ (same noise figure for both values of R_s) at T=300K and f=10kHz.
I need to ...
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Finding the "drop in potential" as current moves through a single resistor of a circuit with parallel resistors
I have four different resistors connected in parallel to a \$24.0 \ \text{V}\$ battery with internal resistance of \$0.500 \ \Omega\$. The resistor values are \$10.0 \ \Omega\$,\$15.0 \ \Omega\$, \$30....
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Finding the voltage available at the terminals of the battery in a circuit with parallel resistors
I have four different resistors connected in parallel to a \$24.0 \ \text{V}\$ battery with internal resistance of \$0.500 \ \Omega\$. The resistor values are \$10.0 \ \Omega\$,\$15.0 \ \Omega\$, \$30....
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Current Direction and Voltage Polarity in Capacitor/Inductor Circuits
I believe that this question may be simple for those with a little more experience, but it is still puzzling me.
Studying capacitance/inductance, I understand that the capacitor in the DC case behaves ...
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Finding resistance for parallel resistors: how is my reasoning incorrect, and what is the correct reasoning?
I have the following circuit:
The voltmeter \$V_1\$ measures the voltage drop across the \$9.00 \ \Omega\$ resistor and has a reading of \$4.50 \ \text{V}\$.
The reading on ammeter \$A_1\$ is \$I_1 =...
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Calculating the reading on ammeter \$A_1\$: why am I incorrect?
I have the following circuit:
The voltmeter \$V_1\$ measures the voltage drop across the \$9.00 \ \Omega\$ resistor and has a reading of \$4.50 \ \text{V}\$.
I am trying to calculate the reading on ...
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How do I find Vo in the circuit?
I1 + I2 = I3
I1 = Vi/Z1 ... Z1 = (1+sCR1)/sC
I1= Vi(sC)/(1+sCR1)
I2= Vi/R1
I3= -Vo/R1
I1 + I2 = I3
Vi[(sc)/(1+sCR1) + (1/R1)] =-Vo/R1
-Vi[(R1sC)/(1+sCR1) + 1] = Vo
How do I change back to time domain?
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How to create 4-bit asynchronous counter?
I am new to Multimedia Logic and am trying to create a 4-bit asynchronous counter. I did something like this, but it doesn't work.
I'm not sure if everything is properly connected and if I was using a ...
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Why is each time constant in this transfer function equal to "open circuit" time constant not "short circuit" time constant?
From this lecture notes, the open circuit time constant approximation:
How to prove the yellow part? The lecture note mentioned Richard Adler at MIT did prove this but I could not able to find his ...
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How to sketch the waveform of the voltage across capacitor and find equation that describes it? [closed]
Below DC voltage source, a switch, resistor and capacitor. At time \$t=0\$, \$C\$ has zero voltage across it and switch is closed.
How do I sketch waveform of voltage across capacitor v/s time and ...
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Where are the transistor number 18 and 21 in op amp 741 according to Wikipedia?
I was trying to implement this op amp from Wikipedia in Proteus :
Like this:
But I could not find Q number 18 and 21.
What is the reason that there are not Q number 18 and 21? Or if this image is ...
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Why does my oven trip the kitchen circuit fuse? [migrated]
After a recent refurb where some of the electrics were also changed (including consumer unit and a full rewire), I noticed that when using the oven it would sometimes trip the kitchen fuse. Where ...
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Is my circuit analysis correct?
This is the circuit.
It is assumed that beta is 99 and VBE=0.7 V for both transistors.
Here is what I've done.
Multisim confirms the first set of values I worked out regarding Q1.
However it does ...
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Find the voltage drop across the capacitor in the LRC circuit
I am having issues finding the voltage drop across this capacitor in the circuit attached.
Attempt: The impedance of the inductor is 50j ohms, and the impedance of the capacitor is -j20 ohms. This ...
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Help me to understand the output signal of this circuit
I want to understand the output voltage of this circuit.
My analysis is:
When we are in the positive half of the wave, the capacitor will charge and the current will flow through D1 after it goes to ...
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Is there any method to turn any PWM DC-DC converter to its small signal model at circuit level?
Is there any method to turn any PWM DC-DC converter to its small signal model at circuit level?
As I know the PWM switch model does that well but it only applies to simple circuits and the switches ...
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Find the voltage across the dependent source
I was trying to do some first order circuits and there was this one that kind of confused me.
Correct me if I'm wrong but if $$V_s=u(t)V$$ this means that for t<0 Vs=0 and for t>0 Vs=1 right?
So ...
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Does anyone know why this diff amp isn't working?
simulate this circuit – Schematic created using CircuitLab
I'm new to electronics and I've been figuring out how a diff amp works. I followed a schematic I found on YouTube.
Basically, as V3 ...
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Resistance measured individually vs measured on PCB
I always wanted to ask this question.
Suppose I have a 1kohm resistor. I measure its resistance by connection a multimeter to both of its terminals (when it is not connected to any part of a circuit.) ...
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