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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1answer
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simple circuit analysis kcl kvl
can i know what, why and how this Rth is parallel / how its calculated?
answer by jonk: thevenin analysis
i mean my solution would be:
I1 = I2+ I
.
I1 = (9-V2)/10k
I2 = V2/20k
I = V2-...
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1answer
40 views
Finding \$L\$ value in simple circuit
Hello and first of all sorry for posting a screen, I don't know how to make my own schematics.
This is one of the excersises from previous year's electrotechnics. The formula to calculate the result ...
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0answers
42 views
Automatic counting of the number of nodes, branches, contours in the electrical circuit
For scientific work, I need an automated counting of the number of nodes, branches, and contours, since need to work with large schemes with a large number of complex relationships. I use Microcap, ...
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0answers
47 views
Delay In circuit
I am working on a mini project using op amp.The circuit uses comparator so when a resistance is changed i.e the Vin is changed(cause I am using Resisters Voltage divider )comparator gives output and ...
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0answers
35 views
Equivalent Circuit of Howland current Pump
Why is at norton circuit for Howland current pump the current source is taken as vi/R1 instead of vi/R0?
Because the formula for Norton current is
IL=In*(Rn/(Rl+Rn))
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1answer
75 views
How is this equation valid?
I am trying to understand the Howland circuit.But how is the following equation formed .Isnt it should be(vi-vo)/R
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1answer
30 views
Function generator output
A function generator is hooked up to two resistors in series.
The voltage across the function generator changes over time, shown by the different graphs
The questions asks to find the output voltage ...
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0answers
34 views
PTT works not as excpected [on hold]
I bought the following headset with a push to talk (PTT) button and four pin headset jack.
If I connect this to my windows notebook the microphone is always on / working. But the curious thing is ...
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2answers
62 views
Differential equation of an OP AMP circuit with RC elements
I have to find the differential equation which describes the relation between input and output voltage for the circuit below. Per how the RC components are arranged, I simply can not find a ...
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4answers
436 views
Circuit Analysis: Obtaining Close Loop OP - AMP Transfer function
Trying to figure out the Close Loop System transfer function of an op-amp, however the math isn't working out as it should.
Circuit In question:
simulate this circuit – Schematic created using ...
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1answer
57 views
Can some one explain me how this equation about op amp came? [on hold]
I dont understand how is the summing of current equation is derived .plz help me to understand it
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1answer
61 views
Thevenin equivalent of the following circuit
So...I have to find \$v0\$ using exclusively Thévenin/Norton equivalents. I am completely lost since in this case I have a dependent voltage source which relies on \$v0\$ itself.
\$v1,a,R1,R2\$ and ...
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1answer
48 views
How do I calculate the voltage across a capacitor when the source is a square wave?
I have a series RC circuit with R= 2.2K Ohm and C=100 nF, and the voltage supply is a 2.5V peak square wave. And I'm not sure how to calculate the voltage across the capacitor.
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0answers
65 views
Why the opposite of the passive sign convention is not the active sign convention?
Studying the fundamentals of circuit theory, I was reading the Wikipedia article on the Passive Sign Convention and found out about the Active Sign Convention (ASC). After searching many introductory ...
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1answer
35 views
Reverse Engineer DIN 5-pin connector
Summary
I have a digitial guitar amplifier that can be controlled via a footswitch. The footswitch is connected to the amplifier via a DIN 5-pin cable. I want to be able to control the amplifier with ...
4
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1answer
119 views
Why is this component that looks like a capacitor with ground lines in this circuit diagram different from a polarized capacitor? [duplicate]
What is the component that is represented with two horizontal lines like a capacitor with three Ground Chassis lines connecting them and a + at the top and a 10μ label.
See picture below (top right ...
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1answer
151 views
Impedance calculation from voltage and current (exponential) waveforms
If we want to find the impedance across two terminals (a port) at a frequency \$\omega_0\$ using the voltage waveform across \$v(t)\$) and current through (\$i(t)\$) the terminal, general intuition is ...
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0answers
47 views
Voltage law not correct [closed]
Is the voltage wrong? Across the resistor there cant be any voltage drop because the electric field of a battery that forces the electrons to move is constant for all points inside the conductor.Just ...
2
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2answers
58 views
Thévenin's Theorem Example
I just started learning Thévenin's Theorem. My textbook gives the following example:
I'm referring to online sources such as this to complete this problem. However, all of the circuit diagram ...
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2answers
125 views
The Art of Electronics (Integrators)
Reading this topic from "The Art of Electronics" : Integrators
How does RC keep V << Vin?
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1answer
19 views
Explanation of Source-Absorption Theorem Example
In the section on the Source-Absorption Theorem, my textbook has the following example:
I was wondering: If the voltage $$v_\pi = - v_e,$$ then why do we get $$g_m v_\pi = g_m v_e$$ instead of $$g_m ...
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0answers
24 views
Changing impedance of load [closed]
For this representation, why is there a change in the variation of the impedance when Zload = R2?
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1answer
33 views
Finding Norton voltage and resistance and max power
My directions for this problem are to find the power delivered when RL=3 and then find the maximum power.
simulate this circuit – Schematic created using CircuitLab
I found Rth = R1//R2 = 1 ...
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2answers
84 views
Thevenins Theorem
Can someone please help, I'm struggling with this circuit. I don't quite understand what I need to do, mainly with whats series and parallel. My tutor is not helpfull in the slightest! He' only given ...
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2answers
46 views
Feedback on a simple motion activated motor circuit
I have been working on a motion activated motor which uses a PIR sensor to detect the motion. The idea is when PIR detects user in front of it motor should start running and when the user moves away ...
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1answer
38 views
Algorithm for getting currents and voltages from resistances in circuit as graph
For my CS project I have to write simple circuit simulator, where I get list of edges of circuit as (a,R,b), where a and b are nodes at the end of the edge and R is it's resistance (it has a resistor ...
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1answer
56 views
What is this SMD part?
I’m trying to repair a powered recliner touch sensor, and I’ve isolated the part that I think is the problem. The issue is, I don’t know what it is! In the first image, you can see that it has three ...
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1answer
114 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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0answers
61 views
What is the Thevenin Norton equivalent of the folloing circuit
I am trying to find the Thevenin Norton equivalent of the folloing circuit. I am familiar with the procedure.
However, when I am taking off the voltages to calculate the equivalent resistance, I am ...
3
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1answer
47 views
LTSpice current dependent current source timestep too small error
I solved this circuit by hand.Which asks to calculate vo and Io in the circuit.
And I tried to verify results with LTSpice.
If I change dependent current source B2's equation to I = I(R1)* 50 it ...
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2answers
71 views
Does connecting LEDs in parallel use more current then connecting them in series in my circuit?
Sorry if this is a dumb question, I need a sanity check on this stuff.
Is it possible to give LEDs varying current, without sacrificing efficiency? Basically I have 4 LEDs which could all use ...
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2answers
105 views
How would I go about converting a change in capacitance into frequency? [closed]
I have to make a model for a pressure sensor. The sensor measures the pressure by changing the capacitance. I only have the datasheet for that.
Summary: pressure>> diaphragm deflection >> change in ...
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3answers
137 views
Why does a capacitor charge faster when there is a diode connected?
In an series RC circuit why does a capacitor charge faster when there is a diode connected in parallel with the resistor?
I tested on an oscilloscope, using a square signal and this is what I got.
...
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1answer
65 views
Solving a circuit with Nodal Analysis [closed]
I've been trying to start solving the circuit for a long time now, but I've no idea where to begin, what node should be grounded. Someone please solve this circuit ina detailed manner
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3answers
73 views
About dynamic equations and the transfer function for the circuit
/
Attempt
Follow my setup
$$v_1=u_2$$
$$i_1=C\frac{du_2}{dt},v_2=L\frac{di_2}{dt},i_2=\frac{u_2-v2}{R_2},i=\frac{u1-u_2}{R_1}$$
According to KCL: \$i=i_1+i_2\$
Let \$s=\frac{d}{dt}\$
Get \$R_2(...
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1answer
32 views
I cannot find information about some chips in 3 stage LNA circuit
Hi, here you can see 3-stage LNA circuit. I want to know information about two chips(6 pins) with R8 mark at the top. Also, 4 chips with D4 mark with 3 pins at right side. Is there anyone who has a ...
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1answer
43 views
This SR latch built with 180nm CMOS does not work in ltspice. How do I fix its behavior and parameters?
EDIT: I copied over the latch from another larger model that had Vdd defined, but missed it when copying over the design. However, after adding in Vdd, I still run into this confusing issue where the ...
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1answer
17 views
altium input/output pin error
I have a problem (stm32f407vgt6) with altium input output pin error. I will use 3.3 volt in my mcu that's why I added 5-3.3 voltage regulator in the circuit but I ve taken this error. Details
VCC0 ...
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1answer
43 views
LED switching: Circuit reacts unexpected
I have my current circuit in LTspice and am trying to simulate it.
The idea is the following: I have a UV LED (360 nm) which I want to switch off in at most 6ns.
For this I have my LED in parallel ...
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2answers
91 views
Question on the Power efficiency of a circuit
I wanted to find the effect of load resistance on the power efficiency of a circuit. When I apply the max power transfer theorem, the internal resistance of a cell = the load resistance right? So when ...
0
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1answer
57 views
Why superposition theorem has not been executed here?
Here is the given circuit
In this problem while finding V1 we didn’t took the voltage contribution at that point by Vo(Superposition theorem)Only current source Is has been used to find the voltage ...
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0answers
92 views
What is the purpose of a capacitor in an ideal op amp schematics?
I'm trying to understand the purpose of the capacitor C which is in parallel with the resistor R3. Current sources IB are indicative of the current offset which was the part of the lecture we had ...
2
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1answer
99 views
Driving IRF9530 MOSFET with 5V
I want to drive the IRF9530 P-Channel FET with 5V PIC microcontroller. My load is 3.2A. schemtic shows one row in my LED matrix. Scanning @ 1/16th rate, so peak current per LED will be 64mA and the ...
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1answer
48 views
Current through a diode changes for the same forward voltage in two circuits
In LTspice IV, I am simulating a 1N914 diode behavior in response to a variable current source in two circuits. One circuit has just the current source and the diode, and the other has the current ...
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1answer
55 views
Trying to have NMOSs in parallel while passing current through only one at a time
If I wanted to have a bias current I1 going through M1 or M2 and I want M1 to alternate between on off (M1 on/M2 off, M1 off/M2 on) would this work? I simulated this with spice and for the first ...
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0answers
47 views
Sizing capacitor in capacitor-diode charge-pump circuit
How I should calculate the capacitor for a frequency of 200k and my output have to be 5 times my input. I know the voltage doubler circuit but in this case i dont know how to do this.
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58 views
Do photodiodes break KVL?
I know what you are thinking, but hear me out. Let's do KVL in this loop:
simulate this circuit – Schematic created using CircuitLab
We get:
$$
-V_{PD}+I(R_s+R_L)-V_1 = 0
$$
Now we solve for ...
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2answers
83 views
How to tackle circuit containing time variable resistor?
simulate this circuit – Schematic created using CircuitLab
For instance above schematic find current as function of time in circuit above
I studied it about months before and am not able to ...
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1answer
34 views
Doing KVL on PNP BJT
I'm trying to find the voltage at the emitter and i use the property they give me of the absolute value VBE where in the book its equal to the small AC signal plus the DC VBE ( in this case that small ...
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0answers
21 views
What is the voltage across a photodiode bellow the Saturation Limit?
This is the equivalent circuit for a real photodiode:
simulate this circuit – Schematic created using CircuitLab
Source. I added a Bias Voltage based on Figure 1-9 (a) of the Opto-...
