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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Usage of General Purpose Diode in Series with Schottky Diode in HP 3312A

I've been taking a look at the HP 3312A signal generator schematic to learn how it works. For reference, the service manual that contains the schematic can be found here: https://bama.edebris.com/...
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1answer
215 views

Q: Homework - Past exam solution Is this the right solution?

I am trying to find Vo but I am not sure If this solution right? Is there a shorter path to find Vo? solution
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Why is the imaginary part absent in the BJT gain calculation?

The gain of transistor Q1 was previously calculated in this post simulate this circuit – Schematic created using CircuitLab It was found to have a gain of about 2.92. Now I change the ...
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2answers
109 views

automatic submersible pump actuation project

I have a project for automatic submersible pump actuation using a microcontroller. I've done for two voltages like 5 V and 12 V and its corresponding relay. Also, in each board there is a transistor ...
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1answer
1k views

Power stage for VCR (Voltage Controlled Resistor)

I'm building a VCR (Voltage Controlled Resistor) using the LM13700 component. You can read more details on that here: Floating voltage-controlled resistor with LM13700: How does it work? The problem ...
3
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1answer
69 views

How to compare Matlab/Theory <=> Cadence: Switched-cap. Integrator: Mag & Phase

I tried to compare the simple switched-capacitor integrator below, between Cadence and Matlab (at the end acting as a simple loop-filter for a delta-sigma). I am stuck now on the point of how to ...
3
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1answer
110 views

Need help with an IR demodulation circuit

I'm trying to reverse engineer a PCB and made a schematic. The bad thing is I only have PCB images from both sides, not the actual PCB. This PCB is used to detect a very small black object spinning at ...
3
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1answer
220 views

Opamp gain calculation

May be a very basic question, I am a chemical engineer with limited electronics knowledge. The circuit is a potentiostat with the current source \$I\$ being a sensor electrode. I was looking for a ...
3
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1answer
280 views

Where does the 1V voltage come from?

I have a four PLC with many digital I/O connected similarly to the schematic below. If I use multi meter and measure the voltage between the two points in the schematic, why is it showing 1V? Isn't it ...
3
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1answer
2k views

How do determine MOSFET parameters in LTSPICE

I am designing a phase locked loop on LTspice (which I'm new to), but have come across a snag in the procedure: Is there a way to determine the output resistance of a mosfet (as the I'm not able to ...
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1answer
614 views

Intuition on Thevenin's Theorem

In the following lecture by Prof. Anant Agarwal at 36:00, he intuitively proves Thevenin's Theorem using the following circuit simulate this circuit – Schematic created using CircuitLab If ...
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2answers
1k views

Designing 4th order Butterworth Multiple feedback bandpass filter

I'm trying to design a 4th order Butterworth bandpass filter using Multiple feedback topology. The design requirements I am trying to achieve for this filter are; Q factor = 10, Av = 11, fc = 100kHz ,...
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2answers
322 views

P-MOSFET Dropper-Switch - Linear Region

I'm repairing an ECU board from a SCANIA generator. It works with 24Vdc, and on the last maintenance the technician powered it with 220Vac, so it blew up some components. I've managed to replace the ...
3
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1answer
298 views

How do I calculate limit frequency of the attenuator circuit?

Calculate the limit frequency \$fg\$ of the attenuation \$v_u =\frac{ u_a} { u_e}\$ at the current source I (for the value given in example), so that for \$f>> fg\$ exist ideal behavior. Note: ...
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175 views

Appoximation of a transient response of a more complex circuit

I have a "complicated" circuit that I want to approximate as a simple harmonic oscillator. More info below. I have a parallel LRC circuit, with some extra input and output load resistors and coupling ...
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87 views

555 PWM circuit set frequency shifting after 2 months

Please refer to post PWM generator circuit review for initial simulation and bugs on the circuit. In general, the circuit works very well and I can control a 12V fan with the PWM output of the 555 ...
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167 views

finding state space equation in x=Ax+Bu form

Can anyone please help me to find the state space equation of this circuit diagram in the form of x=Ax+Bu? The equation I am getting is not giving me square matrix. Can anyone help please? These are ...
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1answer
58 views

karnaugh table issues

Hello,I have this truth table.I did this table and I am creating a demultiplexer 1 in 2.Not multiplexer. Second,I did and that I gave and those Am I right?I want to confirm that I have done it all ...
2
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1answer
239 views

The relation between Vin and Vout (diodes circuit)

Can anyone here tell me if the function I found that relates the Vin to Vout is right? So I made a mesh analysis to find the current in the first mesh (left to right) and in the second and got that ...
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186 views

Left half and right half plane zeros

In the common-source on the left, one can solve for the transfer function and see that there's a right-half plane zero at \$s_z = +g_m/C_{gd}\$. For the source-follower on the right, similarly you can ...
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68 views

Nonlinear circuit and RLC

I'm trying to solve the following question from "Communication Circuits: Analysis and Design" by Donald T. Hess: For the circuit shown in Fig. \$1.P1\$, determine an expression for \$v_o(t)\...
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122 views

Time delay in lumped element delay line

I was trying to analyse a lumped element-delay line by changing the frequency and measuring \$ V_{in}\$ , as shown in the graph the goal of my analysis is to find the time-delay and the attenuation ...
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67 views

Voltage-divider bias common emitter calculations are yielding unexpected results

I performed an analysis on this voltage-divider-feedback common emitter. My result in simulation is relatively close, but doesn't quite check out. Where did I go wrong? I'm new to this and ...
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58 views

How does this timer 555 and transistor circuit work?

Is this the way this circuit works ? If vref = 5v on the pin #5, then Vthreshold = 5v, and Vtrigger = 2.5v With Vthreshold = 5v, if voltage on pin #6 Vp6 > 5v, then Vp3 is Vo = 0 With Vtrigger = ...
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92 views

Voltage Multipler with change capacitor value ratio

I want to ask about Voltage multipler. I understood voltage doubler. By setting the capacitor values ​​of the two capacitors to the same value and setting the voltage doubler circuit, we can obtain a ...
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39 views

Proving the state of a diode in a clamping circuit?

simulate this circuit – Schematic created using CircuitLab So i have this positive clamper right here. So the diode will be ON at a negative source voltage since the anode side will see 5V which ...
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35 views

Adding Line Out / Sub Out to LG soundbar

I have LG Soundbar with wireless sub. I am trying to add Line output, so i could connect a wired sub. I took some pictures of the boards and chips. If someone could point me in right direction on ...
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50 views

How do I find Vs in this circuit with a 2:1 ideal transformer?

How do I find Vs given that V0(to the left) is 10L30degrees? I started by finding that the current on the 10 ohm resistor is 1L30 degrees, and then using kirchoff's law, the current on the tranformer ...
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75 views

Need help for pointing out, source follower circuit with current source, designing NMOS

I'm not sure did I solve this problem right. I made \$ r_{o2} \$ , which is resistance looking at Q2 drain. So I can get $$ g_{m,Q3} = 1.8m(A/V) $$ from $$A_v = \frac{r_{o2} || r_{o3}}{1/g_m + (r_{o2} ...
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1answer
95 views

How to explain the peak frequency and resistance relationship in this op amp circuit?

I was studying thid tutorial by Simon Bramble. I changed the original circuit a little bit and this is the subject of our discussion: As you see, R1, R2 and R3 are all 1kOhm. When I run an AC ...
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1answer
501 views

State Space Average Model of Non-Ideal Buck Converter

I've been learning power electronics and am trying to design a dual-switch forward converter. One of the things I've been trying to do is derive the small-signal equivalent circuit of the non-ideal ...
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45 views

Computing the maximum power that this opamp provides to the load Rl without occurring distortion

Here's the schematic: So first stage is a differential amplifier where vo1 =3.72V in DC (Vin= 0). In this stage i can say AmplVo1 = gainStage1 * AmplVi where distortion only happens when vo1 is ...
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Problem understanding transfer functions of second order filters

The transfer function of any second order filter can be found by analyzing the circuit using the Laplace transform. For example the transfer function of a second order low pass passive RLC filter ...
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94 views

Are there errors in the description of this circuit?

Background The circuit describes the operation of a variable voltage power supply. In the description below the circuit diagram there are errors. Read through the description and note down any errors....
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38 views

Electric power of the light bulbs in a circuit with diodes

Let \$R_1 = 1 \: \Omega, R_2 = 2 \: \Omega, R_3 = 3 \: \Omega, ...R_{10} = 10 \: \Omega\$ be the resistances of the light bulbs depicted in the circuit below and let \$U = 2 \: V\$ be the voltage of ...
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Trouble understanding how dependent current sources affect a circuit (Two-port networks)

While reviewing a problem from my recent test on two-port networks I noticed that it made its way online. When someone was explaining the solution they utilized a point that I just completely missed. ...
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114 views

First principles modeling of op amp CMRR

Introduction I'm trying to analyze an op amp circuit from first principles (i.e. without using the two rules of ideal op amp analysis -- virtual short circuit and infinite input impedance). The ...
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1answer
96 views

Determining gain, KCL/KWL (Basics)

Below is a pi model schematic of a cascaded amplifier. The goal is to find the gain with Rp as load. So the gain would be: \$ A = \frac{V_{out}}{V_{in}}\$. So i set out to find \$V_{out}\$ in terms ...
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1answer
231 views

Thermal Noise in Oscillators

let's consider this circuital model for an LC oscillator in which the parasitic resistance R is affected by thermal noise (represented here with an equivalent noise current source, according to the ...
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113 views

Op-Amps in custom current limiter acting strangely

I'm building a small current limiter (~20 mA). It's important that there is little drop over the current limiter and that the load receives almost the full supply voltage when it's pulling less than ...
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65 views

Circuit Analysis: Difficulty in obtaining a current through a resistor?

I'm solving a problem that requires I compute some impedances, and then the current through a resistor. I obtained some of the impedances*, but don't know how to get the second part (current). ...
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107 views

Relationship between base resistor and collector current in this unbalanced differential amplifier

For this BJT circuit, I was wondering if there was a solution for how the collector currents change with respect to the value of the single base resistor. This arrangement popped up in a circuit I ...
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285 views

How does an op-amp work without proper power supply?

I have built a chua's circuit following this diagram: Source: Kennedy 92(pdf). The rectangle inside NR is and eight pin dual opamp. Then, I remove the 9V battery on the right. It is replaced by a ...
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2answers
370 views

Parasitic insensitive switched capacitor circuit

I'm trying to simulate the parasitic insensitive switched capacitor circuit shown here: I am using cadence virtuoso. My input is a sine wave of 1 V amplitude, 0 DC and 1 kHz frequency. I am using ...
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706 views

Admittance, Conductance, Susceptance definition

Admittance is the reciprocal of impedance. But: 1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ? 2) Conductance is the reciprocal of resistance, or the real part ...
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293 views

What are limitations of Millers theorem for amplifier?

I mean to say that are the two circuits one original and other its miller/ drawn exactly equal in all respects or their are some difference in some respect if so please mention. I am not able to ...
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1answer
1k views

RLC Circuits at t=0 and infinity

For this circuit I need to find \$V_C(0)\$, \$V_C(\infty)\$, \$i_L(0)\$, \$i_L(\infty)\$, \$V_C(t)\$ when \$t>0\$ and \$I_C(t)\$ when \$t>0\$. simulate this circuit – Schematic created ...
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107 views

Voltage increase by connecting Voltmeter

I've got this scheme. V1 and V2 are voltmeters without their own power supply. (V1 gets power from the measured circuit, V2 is powered separately, but in this case from the same power supply.) The ...
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221 views

Second Order Circuit, Sadiku's Fundamentals of Electric Circuits

I would like some help with Sadiku's exercise about second order circuits. I did'nt understand why the solution says that V (0) = -30 V. Also, I did not understand why the capacitor's voltage (Vc) ...
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Q: Finding the current through the capacitor

Having a hard time trying to find the current through the capacitor I don't know what method to use. simulate this circuit – Schematic created using CircuitLab This is how far I have gotten: ...

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