# 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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39 views

### Electric field in a circuit and potential drop

With reference to the above image: Here the battery produces a constant (will it be constant? pl. explain) electric field across the length of the wire, lets say its value is $\vec E$ . This field ...
51 views

### What is the reasoning for the presented equations? How do they relate to "nodal analysis" and figure 1.21?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
81 views

### Zero-cross detector does not detect all the zeroes

I'm trying to do a zero-crossing detector but it is only able to mark half the number of zero passings. It seems to work fine with input voltages of 10-20V, but when using a +120VRMS it checks only on ...
107 views

### How does one know that the current is flowing downwards through the $8 \ \Omega$ resistor?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
32 views

### Calculate the integral of a saw tooth wave

My question is with reference to this question over here Suppose, I have a saw tooth current source with peak value from 0A to 1A with a frequency of 1kHz and I need to calculate the charge of the ...
54 views

### Why is the polarity of the $3 \ \text{V}$ source necessary to calculate the current flowing through the $8 \ \Omega$ resistor?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
91 views

### How can I solve this opamp circuit?

I am designing an Analog Front-End circuit for an NTC Sensor which has 3 parts, the non inverting stage, the low pass filter, and goes to seeeduino. Basically the input voltage is 5Vcc and I need to ...
40 views

### Solution Verification: Thevenin Equivalent with Dependent Voltage Source

I am currently self-studying through MITs 6.002 Spring 2007 course. There are currently no solutions for the assignments afaik. Normally, this isn't an issue, but I am having some trouble with this ...
114 views

### What are the caveats in this circuit design?

My question relates to the circuit in the image below. I have a non-inverting amplifier that generally will need to operate as a buffer (voltage follower) after a low pass filter to give a low ...
78 views

### Can FPGA logic be represented by a matrix/sequence/chain/expression?

There is an interesting paper from our chemistry peers, where they achieve to represent molecules into a sequence of characters. This obviously inspired me to think that there must be something ...
1k views

### How to compensate noise at the output of logic gates?

I am simulating 74HC logic family on LTSpice. The output of inverters and D-Flip-Flop are normal, but the output of NAND and AND are noisy . How can I compensate or filter that noise? What kind of ...
15 views

### Source Transformation Finding TEC

I have been trying to find the thevenin equivalent circuit with respect to nodes a and b using source transformation. I end up having this setup. What would possibly be the next step I should do? Can ...
37 views

### What is the I_R current for this avalanche photodiode?

This is the datasheet of the APD I got. There's 'I_R' at test condition for breakdown voltage. What is this current I_R?
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### APD (avalanche photodiode) responsivity problem

I'm experiencing a few problems with responsivity of APD (model: First Sensor AD500-8-S1). This is the circuit I tried to make. Just simply apply voltage (positive polarity) to the cathode for ...
132 views

### Average value and RMS value

I am trying to understand the concept of RMS value. From whatever I have read and the tutorials I have seen, I have seen them derive the RMS value only considering the first positive half cycle of the ...
47 views

### MOSFETs and circuit interconnection

simulate this circuit – Schematic created using CircuitLab This circuit works fine, but when I put a motor that draws a lot of power (10-14A), it starts and stops. Actually, the circuit on the ...
55 views

### RL-circuit using Laplace

I have a series RL circuit (with zero initial conditions) and I want to find the voltage across the inductor. The formula I got is: \text{V}_\text{L}\left(t\right)=\int_0^t\text{V}_\text{in}\left(\...
115 views

### What is the invisible layer between Boolean algebra and the physical circuit of a computer, and how to understand it?

How is Boolean algebra implemented through a circuit ? Is it just a way of thinking about a circuit? You don't need Boolean algebra to think about a circuit since it is made of physical components, ...
63 views

### Logic state explanation

If the start push button is pressed, is the logic level at RA5 1 or 0?
65 views

### Inductor voltage not decaying to 0V by t=5 TC

In a new lab I have the following circuit: The inductor will change from 200mH -> 400/600/800mH. I am starting with 800mH. The function generator is a square wave at: 50Hz, 20 ms period, and ...
31 views

### Can I use any variable 0v-5v source to engage ebike controller to work as if it had a twist style hall throttle?

The hall throttle plugs to a 3 wire connector. 5v, signal and ground coming from the controller goes through the hall throttle and is reduced to 0v-4.2v for a variable speed control. My question is, ...
60 views

### 2nd Order Circuit

just want to check whether am i doing correctly? How do I know when should I find Voltage ODE and when should I find current ODE? Thank You Update: Vc(0) shld be zero.
104 views

### Diode behaviour in a simple circuit

I have tried using the formula: $I_d = I_s \cdot e^{V_d \over V_k}$ where $I_d$ = diode current, $V_d$ = diode voltage and $V_k$ is a known and given voltage. I got nothing. Edit: here's what ...
52 views

### Understanding the reasoning behind these power calculations involving voltage and current sources in circuits

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.6 Circuit Elements gives the following example and practice ...
53 views

### RC circuit waveforms not lining up on oscilloscope (capacitor starting negative)

I have a lab for a circuits class and in it we are building an RC series circuit with a square wave input. I am using a function generator to produce a square wave at 50Hz, period = 20ms, Amp = 500mV,...
31 views

### Mesh Loop Analysis

I need to figure out how to get the current, but I'm not sure how to do this while only having two resistors. I have tried, but my answer is not matching my measured values
54 views

### Scaling an analog output using an opamp

I have a circuit which utilizes a hall effect sensor and reads out an analog value. The range of the output is between 0.2V and Vcc, which in this case will be 5V. I want to scale that value so that ...
567 views

I have 9 thermistors arranged in a grid, and I want to average the readings from these thermistors without code (that is, average them in a circuit rather than reading all the values into a ...
82 views

### How to invert a signal after inverting voltage divider

I need to bring the voltage from 0-5 V to 0-1 V so I'm using an op amp, for linearity, in my design. The inverting op amp has a gain = $-R_1/R_2$. My output signal is inverted, but I want a non-...
91 views

### Why is EMF = I(R+r)?

A voltmeter is connected to a dry cell battery. The voltmeter reads 9 V. A 24Ω resistor is connected across the terminals of the battery and the voltmeter reading becomes 7.2 V. Calculate the internal ...
42 views

### In this question, can i use node analysis method by assuming Δv and Δi is zero in the 1st step of incremental analysis? [closed]

Consider the circuit in Figure 4.66. The voltage source and the current source are the sum of a DC-level and an AC-perturbation: v = V + Δv i= I + Δi such that V = 30 V (DC), I = 10 A (DC), Δv = 100 ...
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### Diode and voltage divider

I'm having issues with this very simple circuit. I'm trying to identify the different values that the output Vs can take considering that the voltage threshold of the diode is 0.7V. Ve is also a sine (...
43 views

### fitting using unstable poles

I am trying to take into account the frequency dependent behavior of R and L in an LTspice simulation. So I fit their frequency behavior using Vector fitting technique and deduce the equivalent ...
20 views

### Pushbutton doesnt enable buzzer in Tinkercad

I'm trying to build this circuit in Tinkercad. The goal is to charge the capacitor and make a sound with a buzzer if the button is enabled. The capacitor connection is suspicious because if I remove ...
78 views

### Parallel RC circuit differential equation for a mechanical engineer

For a mechanical engineering course in controls, I was asked to Write the differential equation, state equation, and transfer function for this circuit That's the full text of the problem, and the ...
61 views

### Using mesh current method find current and power in 15 Ω and 3 Ω resistor branches of the circuit

I assumed i1 in the left-most mesh, i2 in the right-most mesh and i3 in the top mesh, all clockwise. i2=-2 A from the circuit The equations I got were: from left mesh: 11 - 14 i1 + 12 i2 + 2 i3 = 0 ...
45 views

### A/D Converter with Hall Effect Sensor

I am trying to produce a circuit that uses the output of a hall effect sensor and feeds it into a A/D converter. I have a couple of questions about how this process will take place. Below is a circuit ...
157 views

### How can this 74 series Inverter circuit be analyzed?

I'm trying to analyze the keymech scanning / sampling circuit in the WASP synthesizer So far I understand that the keymech is sampled one key at a time by the 74 series logic driven by the dual ...
78 views

### Not able to find voltage between points A and B [closed]

I want to find the voltage between points A and B, but I am unable to do so because of R3. Can someone please tell me how to find the value theoretically? The answer comes out to be 30.8V when I ...
81 views

### Op-amp with AC input

I've just started learning about op-amps and something confused me in one of my lectures (apologies for the low quality, it's a screenshot): The output voltage is going into a rotational electro-...
41 views

### Problem for 3 mini water pumps controlled by transistors with Esp32 Wemos UNO

Hello everyone I'm doing my project controlling three water mini pump by one board with transistors BC337. The pin will give power when touch sensor sensed something which is embedded in the esp32. ...
35 views

### How to signal and control a salvaged speaker amplifier circuit to turn on

I am trying to convert a dvd/theatre system into a stand-alone speaker amplifier. I have removed the dvd/radio parts and I have the power amplifier parts. The parts I removed with the on button uses a ...
41 views

### Calculating missing partial currents and resistances

I have the following task: The circuit shown is given. The total current $I$ and all partial currents $I_{1}$ to $I_{6}$ as well as the voltages at the resistors $R_{1}$ to $R_{6}$ are to be ...
65 views

### How to analyse a circuit containing a diode? [closed]

I have solved part (a) but I need help in solving (b) and (c). What does Pzmax=500mW mean? I am asking only for the methodology. I editted my solution
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### Need help identifying power potential of a circuit [closed]

This unit is an ESC for a brushless motor. I need to know the maximum voltage it can handle; I keep blowing 25V, 2200μF capacitors while trying to run 48V on it. Secondly, what capacitors should I ...
74 views

### Solve a circuit with mesh analysis. R3 is a negative resistor

The problem I am trying to solve: Solve a circuit with mesh analysis. R3 is a negative resistor My attempt: loop ı1; 15=1*ı1-3.3(ı1-ı3) loop ı2; 10=2.2(ı2) loop ı3= 0=-10+5.6(ı3-ı4)+-(-3.3)(ı3-...
138 views

### Voltage vs frequency in RLC circuit

https://www.eeeguide.com/voltage-and-current-in-series-resonant-circuit/ Here is the graph b/w V vs f. Why at some particular frequency (fc), the capacitor voltage goes beyond supply voltage (Vs) ...
86 views

### Is 24V enough to power this optocoupler

I am using this proximity sensor (E1 NPN) with a Raspberry Pi. The sensor outputs a 24V signal when triggered, which I need to step down to 5V so as to not blow out the Pi. My plan is to use this ...