# 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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### I don't understand Schottky bridge in op-amp circuit

I was going through a circuit and got confused on a bridge part. I am not very good in circuit analysis. Can anyone guide me the working of attached circuit and what is the role of bridge in such kind ...
48 views

### Not understanding current direction for this specific circuit (very basic question)

For the following circuit, I am for some reason just having troubles with understanding why the current (circled blue) moves in the up direction across the capacitor. Or for example, this following ...
2k views

### How does a NAND gate work? (Very basic question)

I'll preface this question by saying that I am a software developer just starting to learn the basics of electronics, so it's very likely I'm missing some fundamental intuition here. Below is a ...
61 views

### LEDs sharing negative output from driver issue

I am having an issue with the above circuit when LED DRIVER B has 0 PWM and LED driver A is being driven by a signal driver B is supposed to be off but the leds from BANK B are still lit dim. I ...
31 views

### determine the Laplace domain of this RL circuit

I am currently learning control system design. I have a lot of confusion about the initial conditions of the inductor in the circuit. Could someone please correctly solve this by getting the ...
45 views

### How to solve the transfer function for an op-amp circuit?

I've been struggling with this problem for a bit now. I'd like if someone could check my work on finding H(jw) or guide me through an easier path, thanks. Here is ...
109 views

### Calculating base-emitter current of a BJT, with emitter connected to ground (no resistor)

Much like the circuit above, most BJT amplifiers use an emitter degeneration resistor to stabilise the bias. It's relatively straightforward to calculate the base and collector quiescent currents. I ...
67 views

### Op-Amp analysis without using op-amp gain

I have a question concerning this op-amp problem for which I need to find an expression for $v_{out}(t)$, where $V_B$ has a constant value: simulate this circuit – Schematic created using ...
18 views

### MOSFET current mirror with compensation

I am trying to understand the difference between a MOSFET current mirror with and without compensation (Replace Q3 with a short circuit). In the case of a current mirror without compensation, V1 ...
122 views

### Charger for lead-calcium battery circuit

I post it because i want to know if anyone of you see any rare in this circuit made in proteus 8.6, i accept any observation, this circuit provide 12v of output and 3 modes of charging fast(15 A), ...
53 views

### Nodal analysis of a basic DC circuit

I am trying to find the v1, v2, v3 and i5 using nodal analysis. I gave the name to the current over the respective resistors i3 and i4 and put it as i0 - i3 - i4 = 0 also write the equations as i3 = (...
132 views

### analysis of two stage preampplifier

I found this circuit in an old book. It is a two stage audio amplifier I wanted to try it but I didn't know how to do the dc analysis. I couldn't find any current. Could you help me to find a ...
555 views

Whenever we load a circuit, there's a drop from the open circuit voltage $v_{oc}$ due to the internal source resistance or Thevenin's resistance$R_{th}$. So we need to have an $R_{load}$ that ...
32 views

### Common base bias divider resistances

I have been trying to grok the common base amplifier, and put together a few examples, but there is something that I do not get at all. I have the setup below. Things are working more or less as ...
59 views

### Will I be able to keep this circuit on by routing the emitter to the base?

I'm modifying a current-limiting circuit to work with a transistor instead of a switch. This circuit amplifies a voltage across a sensing resistor via a differential amplifier op-amp configuration. ...
42 views

### Can I use this garage door circuit to power an ESP8266 [closed]

So this circuit is from my garage door opener. Basically it has 24VDC coming into it which runs directly back to the motor unit of the garage door opener. My limited understanding says that there is ...
95 views

### Converting between series and parallel circuits

I have an RCL circuit which which is coupled to an RC circuit via a coupling capacitor, $C_{c}$. When the system is on resonance, $\omega = \omega_{0}$ the impedance of the RCL is purely resistive,...
63 views

### Diode circuit analysis solution

I am not familiar with circuit analysis, although I can manage to solve basic circuit. However, I am currently stuck with a problem and I am not sure about the solutions. If anyone could have a look ...
88 views

### Subthreshold Analog Accelerator - How is current derived through two sub-threshold transistors in series?

Was browsing the following paper: Fick, Laura, et al. "Analog in-memory subthreshold deep neural network accelerator." 2017 IEEE Custom Integrated Circuits Conference (CICC). IEEE, 2017. When I ran ...
45 views

### Voltage drop polarity

Consider the below circuit : According to my textbook Vs will be However I have another solution which is different from this. Using superposition, we will first find the drop due to the voltage ...
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### Is it possible that a load can be destroyed if I am disconnecting all other loads in the circuit but one?

I consider myself as a beginner, so please don't be that hard to me. Can I theoreticaly destroy a unfused load if I disconnect all loads but one in the same circuit? In my understanding the current ...
65 views

### Thevenin's Theorem: Why is there a $R_{th}$

Consider a linear mess present inside the box, simulate this circuit – Schematic created using CircuitLab If there's a voltage drop $v$ across the load, then why cant we simply replace the ...
48 views

### MOSFET output voltage vs. gate voltage

I don't understand why I am getting this behavior from my MOSFET circuit. Either because I'm not using LTSpice correctly, or I'm not understanding MOSFETs. I set up the voltage to the gate to be a ...
27 views

### Finding the current in a circuit containing diodes

I am working through a problem where I am determining the state of a diode, as shown in the picture below. I have first assumed that both diodes are conducting, and to check this, I am checking to see ...
34 views

### General second order circuit

I was trying to follow the solution for this problem and got stuck in the last portion of the solution. I encircled the part that I did not understand. I can't figure out how the solver was able to ...
39 views

### Can I take the voltage across diode to be same as the input voltage in a limiting circuit?

My doubt is a trivial one, can I take VD1 and VD2 to be V1? If so doing that doesn't make sense to me 'cause when the current flows VD1 is certainly not equal to V1. This isn't a Homework question, ...
27 views

### Buck converter design using MCP1630V

I have already designed a buck converter with the following specifications using an MCP19035: Vin=14V, Vout=1.8V, Fc=63kHz(Crossover frequency), Vref=0.6V, Iout=10A step load High IOH=7.5A step ...
22 views

### Transfer function with separate time delays in each term

We've been given the problem below for our current assignment As far as I can recall, I have never seen a transfer function with time units in the function itself, added onto each separate term. I ...
48 views

### Calculating current and voltage from RL circuit through differential equation

Our circuit, where R1 = 3 Ohms, R2 = 1 Ohm, R3 = 2 Ohms, L = 5 milliHenry, and I = 0.01 Ampere. Trying to figure out the differential equation for this circuit, as well as the current for the ...
51 views

### Second order opamp circuit problem

I was trying to understand the way this problem was solved and I got confused with the latter part of the solution. I encircled the part that confused me. They seem to contradict each other. If dv(0+)/...
33 views

### In a forward bias diode, why do electrons continue into neighboring holes?

When an electron from the n-type side fills a hole on the p-type side, it fills the valence shell. For reference, consider this video: https://youtu.be/7ukDKVHnac4?t=230. I learned in chemistry that ...
3k views

### What is the role of the transistor and diode in a soft start circuit?

Please can someone explain the purpose of both the transistor and diode in this soft start circuit
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### Why are these measurements misleading and how do I fix them?

I am trying to measure the voltage between node 2 and 3, which I am guessing should be zero. With a multimeter I read 0V. With an oscilloscope I am reading about Vb/2 if I remember correctly. Why are ...
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I've been trying to make an extremely simple AM receiver (without even a tuner), however, it doesn't seem to be working. As shown in my schematic, what I did was connect the antenna wire to the base ...
123 views

### Why is i(inifinity) equal to 21 A

Image is from Fundamentals of Electric Circuits 6th Edition, Alexander and Sadiku. Page 314. ...
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### How does one relate an RC circuit's time domain solution to phasors?

It seems to be a given for phasor analysis that the voltage across a capacitor can be defined as follows: $$V_{C}(t) = V_{A}\cos(\omega t + \phi)\tag{1}$$ Where Vc(t) is the capacitor's voltage at ...
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### Simulation of a chopper type E (four quadrants) in pspice

Im trying to make a chopper working in the four quadrants based on these idea translated to this circuit But it cant be simulated, psice gives the next log ...
40 views

### SIM800L Disconnecting Issue

I'm doing a project using SIM800L ebay module.I can send & receive SMS & calls. The problem is, on workbench its working, but in actual site environment when the GSM signal is low & it ...
74 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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### Determining the Thevenin Equivalent

How could I proceed with this circuit to determine the Thevenin Equivalent? I have the values of $R_1, R_2, R_3, I_2$ and the time value for g. I first tried to figure out the total voltage for the ...
19 views

### Circuit component controlling charging current [duplicate]

I wonder how the circuit of a typical 5V phone charger looks like. In the figure given below, I sketched how I imagine it. Using this setup, could I control the current drawn by the phone by selecting ...
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### How does this negative voltage generator work?

I managed to fry a piece of moderately rare equipment due to connecting it to the wrong voltage power supply, and I'm now trying to diagnose what's wrong. Luckily, reverse engineered schematics are ...
58 views

### Everyone knows this thevenin equivalent, but is it the same as this?

My question is, in the picture on the right can we switch the voltage source and the resistor and everything will still be the same? the circuit would look like b-Rth-Vth-A. Will everything still be ...
86 views

### Simple op amp circuit question

I have to find $V_o$ (voltage over $R_3$), $I_o$ (current through $R_3$) and the power absorbed by the 1 Ohm resistor in this circuit: simulate this circuit – Schematic created using ...
50 views

### Frequency compensation circuit

simulate this circuit – Schematic created using CircuitLab The diagram above is part of my constant current circuit which function as frequency compensation circuit. I was given the time ...
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### How can I achieve 5V DC from 230V AC wirelessly? [duplicate]

I want to step down 230VAC so that I can have a large amount of current that I can transmit wirelessly through the transmitter coil to the receiver coil. I want to transmit it across 5millimetres ...
368 views

### Why does the small signal analysis work? (Intuition)

Consider the Large and small signal model of the MOSFET amplifier, simulate this circuit – Schematic created using CircuitLab How is this transformation valid, I get the linearization of the ...
72 views

### Parallel circuit with LED on one path and resistor on the other

I'm a beginner to circuits. Unlike many other questions, my circuit involves a parallel circuit with a LED on one path but a resistor on the other, as shown in the picture. Q1: assuming the LED has ...