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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Can the lens from an MLX90614-DCI sensor be transferred to other MLX90614 models to limit the FOV?
After discovering my misconception about the temperature range of the MLX90614-DCI version—which is actually -70°C to 270°C rather than the -70°C to 380°C I initially believed—I decided to switch to ...
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Determing the line and load regulation of a Zener MOSFET regulator
I am working on a circuit involving a bridge rectifier, a smoothing capacitor, and a Zener-MOSFET regulator. I need help finding a mathematical representation of line regulation and load regulation of ...
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LTspice resonant circuit simulation: Output not building up as expected
What changes should I make to get the output buildup continuously in the simulation, until I get some warning, maybe "simulation out of bounds?"
What is this underlying frequency of around ...
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Input Impedance of capacitive amplifier
I am analysing the input impedance of a capacitive amplifier as shown below in fig 1 and 2.
The two circuits are identical except at the input. Fig1 has two differential voltage sources and Fig2 has ...
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How do I use the given voltage drop across \$R_3\$
I can't figure out how to solve this circuit if I use mesh I get these 3 equations what is the fourth equation?
$$
24E3*i_1 - 12E3*(i_2+i_3) = 24-v_{52} \\
-12E3*i_1 + 25E3*i_2 - 10E3*...
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Short circuit fault in step down transformer
A step down transformer connect a high voltage network and secondary is open. The question is what happened when short circuit in two terminals of hv side?
Does the short circuit current through the ...
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Second order all pass filter with variation in Q in numerator and denominator
This is a problem from Microelectronic Circuits by Sedra and Smith.
Consider a second order all pass filter of the form:
$$T(s) = {a_2} \frac{s^2 - s\frac{ω_0}{Q} + {ω_0}^2 }{s^2 + s\frac{ω_0}{Q} + {...
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How to Accurately Simulate a Wideband Bias Tee in LTSpice?
I'm currently working on designing a wideband bias tee and have been using LTSpice to simulate its performance. However, the results I'm obtaining seem too good to be true, and I'm concerned there ...
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Help in understanding proposed circuit to measure plasma current
I am working with a plasma where we bias an electrode with a voltage and the plasma acts as a source of current to the electrode. We calculate the plasma current by measuring the voltage across a ...
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is there any GUI tool to see cir files in schematics?
I am using NGspice to simulate circuit. As you may know, the netlist format in ngspice is cir.
The following is my simple circuit.
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Simple circuit analysis question, voltage across an unknown component
Question: Joe was debugging part of an experimental apparatus, probing around with his voltmeter. Part of the apparatus had two
obvious resistors in series with an unknown element, as shown in the
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Why is the LTspice simulation behaving differently in these identical cases?
Case 1: Capacitor initial voltage initialised using .ic command, IC not grounded.
Result: Simulation is incorrect. Initial condition not being used.
Case 2: Capacitor initial voltage initialised ...
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Question about PIC16F18345 Evaluation Board
I am trying to understand the schematic of MPLAB® XPRESS PIC16F18345 EVALUATION BOARD.
However, I cannot understand the following parts.
Why there are 2 microcontrollers (PIC16F18 and PIC16F14) on ...
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Single-Ended Equivalent Circuit for a fully-differential opamp circuit
I have a question regarding the single-ended equivalent circuit for a fully-differential-opamp-based circuit.
This is a fully-differential-opamp-based circuit:
The opamp has a voltage gain of A0 and ...
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Why does this power supply switching not work?
simulate this circuit – Schematic created using CircuitLab
I have a voltage source (a LiPo battery). It powers up a voltage divider made of two resistors of 220k and 1M. The 1M resistor can be ...
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Why is my inductor behaving like a capacitor?
I have an inductor coil (3 spools are connected in series) & I wish to find its inductance.
I tried using a multimeter to measure the ...
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Is it true that a sine wave is the only signal that does not change shape in a linear circuit?
This is from Microelectronic Circuits by Adel Sedra and Kenneth Smith.
The book says,
In fact, the sine wave is the only signal that does not change shape
as it passes through a linear circuit.
Is ...
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Laplace vs Fourier transform: Which you recommend for steady-state circuit analysis?
(1) obtain the transient target voltage (or current) using the Laplace transform, and then calculate the limit t -> inf.
(2) use Fourier transform
Thank you.
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I found a simple op-amp circuit online, which confused me
The following circuit is simple. Due to its short output to input, the output will follow the input.
Besides that, I would like to understand the op-amp behavior, which is confusing me.
As I ...
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Trying to understand the exact math behind use of decoupling capacitors
From what I have read so far decoupling caps help in reducing the supply droop due to trace inductors in case the load draws large current transients. The capacitor works to supply the current ...
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What is causing the spikes at the negative terminal of the opamp in response to the square wave?
I have a simple inverting amplifier as following in which the input is a square wave. By virtual short I expect node VF2 to be at 0V, but when I plot the voltage at VF2 I see spikes that are in sync ...
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Nodal analysis using matrices - Wrong math?
I am attempting to solve a (not so difficult) circuit using nodal analysis
However I am getting 0V for half of my nodes, which is clearly wrong, the results violate KCL
Method
I am using nodal ...
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Can someone explain the working principle of this diagram?
In my opinion, during daytime because our battery is only 3V, the solar panel produces more voltage and because of voltage difference, voltage flows from solar panel to battery and there is no ...
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PUT relaxation oscillator problems
While trying to learn more about electronics and oscillators, I encountered the following post on this forum PUT relaxation oscillator doesn't work. I decided that I would build the circuit which &...
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Why is the output impedance of an open-loop amplifier with a loading effect calculated by breaking the loop like this?
I'm a bit confused about how the author calculated the output impedance of the open-loop transconductance amplifier with the loading effect as follows.
(All images are taken from of the 6th edition of ...
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Load cycler keeps stalling at same voltage
Hello I am building a load cycler using an arduino with this code:
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How the GPIO works internally?
I have a fair understanding about how to configure as input/output enable pull-up etc. While going through the datasheet of ATTiny85 Section 10.2 (The same diagram also there in ATmega328p) I have ...
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How to determine exact output impedance of the source degeneration using feedback analysis?
How can I get the EXACT output impedance when looking from the drain side of the source degeneration using FEEDBACK ANALYSIS?
It can be derived easily using a couple of methods, but I'm having some ...
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Can we solve all linear circuits using only KVL and constitutive relations?
Can We Solve for Node Voltages and Branch Currents in Any Linear Circuit Using Only KVL and Constitutive Relations?
In circuits with a single loop, it's trivial to solve using only Kirchhoff's Voltage ...
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Constant volatge at the output of LM311
I made a PCB based on the following schematic.
The inputs of the comparator work as expected (i.e., the capacitor voltage or the voltage at the non-inverting pin gradually increases and, after a few ...
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What is the correct formula for the 3 dB frequency of an RC or LC Circuit?
Before we jump to another post where the formula is
I am reading through the text book Microelectronic Circuits 8th edition by SEDRA/SMITH. In the text, they show this table.
Here it shows the time ...
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How should I apply FACT technique on this circuit?
I am learning the fast analytical circuit technique. How could I calculate the pole in the circuit below? I also calculated in the "traditional" way.
I was able to determine the zero and ...
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demultiplexers and multiple output selection [closed]
In a DEMUX, is it possible to route 1 input signal to multiple output signals? Say input I is routed to both output 1 and output 2. Does this scenario have anything related to data collision?
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Help with circuit analysis - Transistor, dc-motor, arduino, resistors
currently I am trying to improve my skills in electric circuits by small hobby project. I want to spin one mini dc motor, which is just spinning if the Arduino activates the flow of current with a NPN ...
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RC circuit equation why have negative sign
I'm reading a book named The Art of Electronics.
What are some of the features of circuits with capacitors? To answer this question, let’s begin with the simple RC circuit (Figure 1.31). Application ...
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3-Phase system Voltage conversion
If we are converting from Y to delta configuration or vice-versa, how do we convert the phases of our voltages? I've seen that we need to add or subtract 30 degrees from one another, but I don't ...
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Nanogrid management PCB review
I have made some progress on the PCB for a nanogrid consisting of solar panel, wind turbine, batteries, load (not yet connected) this board monitors the current/voltage of each components and sends ...
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Why does this transistor amplifier fail if Rc is greater than 50 ohms?
This simple circuit amplifies a 1 µV 50 ohm 7 MHz signal (e.g. RF off an antenna) quite nicely (31 dB):
However, I'm stumped as to why R2 must be so low (50 ohms), giving a Ic of close to 50 mA. ...
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The role of Q33 and the connection of pre-discharge circuit in the BMS circuit
I'm trying to understand the following circuit which is taken from the TI's TIDA-010216:
I don't understand the role of Q19, D29, D30 and Q33 in the circuit. According to this post, it seems that Q19,...
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Why does tan (θ) equals -j in impedance of reactive circuits?
I'm having trouble understanding the maths for impedance.
Suppose we have a voltage of \$V(t)=V_{0}sin({\omega}t)\$ and we plug this into the capacitor equation \$I(t)=C\frac{dV(t)}{dt}\$. This would ...
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Does KVL guarantee identical voltages/currents in similar circuits?
I have a question that is a bit abstract. Assuming I have two proper linear circuits, A and B, which have:
The same ideal components (for example, voltage source, inductor, capacitor, resistor)
The ...
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Where should I take the measurement from to find the correct attenuation level of a resistive pi attenuator?
I am currently designing a resistive attenuator for an RF project I'm working on. I wanted to have several resistance combinations to obtain various attenuation levels (1-8 dBs). When I calculate the ...
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Calculating the poles of a Circuit
I have been reading Behzad Rahzavi's Analog Design book to prepare for interviews and have come across a discussion on calculating poles that confuses me.
In the following example 6.15 the book ...
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KVL and KCL for an RLC circuit
I have a circuit for a resistor \$ R \$, inductor \$ L \$, capacitor \$ C \$. I also have two sources of power, \$ u_1(t) \$ and \$ u_2 \$. My task is to set up a state equation for the circuit, and I ...
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3x3 nodal analysis. I know v2 but I don't know how I can use v2 to find v1 and v3
I tried KCL but I don't know what to do from there. I hope someone can show me how to do it.
This is how I figured out v2 is 12 V.
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How are opamp node voltages being set in the following circuit and what is the use of the diode configuration?
I am using a PCB which has the following opamp configuration implemented. It's supposed to be a precision buffer for the source V3. I accidentally connected the source V4 as well and observed strange ...
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How to short time delay controller?
I have an old keyboard which I use for decorative purpose. It has RGB lights which turns on for few seconds when a key is pressed. I want to keep them on at all times. How to achieve this? Can I ...
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Working of differential pair using MOSFETs
I am currently learning about differential pair using MOSFET from this course. In this particular lecture, the teacher says that to have a differential pair we need to apply the second signal v2 at ...
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Do you know this circuit? [duplicate]
I was checking the flipper Zero Wi-Fi Developer Board schematics and in the power section I bumped with this circuit, but I've never saw it before. Someone knows the name of the circuit or its purpose....
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Why does a MOSFET fail on fast signals, even if they're much longer than the turn on + turn off times?
When running at a fast signal, why does the MOSFET below not turn off, even when gate voltage is well below threshold (even negative)? Although the signal is fast (7 MHz, 140 ns period) it is < 1/...
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