Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network.
-5
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2answers
58 views
Why is there no current over resistor next to node?
[n00b alert]
I'm wondering why there's no current across the 4-ohm resistor.
1
vote
1answer
44 views
Switching between two devices
I want to switch (toggle) two devices using one GPIO pin and basic components. To achieve that I designed circuit containing one FET driving first device and two FET transistors for driving second ...
0
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3answers
47 views
Find v1 and v2 of a summing amplifier when it is in series with another Op-Amp
There is a summing amplifier with two AC power sources (v1+v2,) each connected to a different Ground. Each of these sources connect to a resistor (R1+R2,) and then to a summing point, which branches ...
-3
votes
1answer
63 views
RLC circuit step response
In this given circuit, how can we find \$ Vc(t) \$ that is voltage on capacitor?
\$ u(t) \$ is step that is 0 when \$ t<0 \$ and 1 when \$ t>0 $.
I want to find \$ Vc(t) \$ by 2nd order ...
2
votes
3answers
61 views
Why reverse polarity causes damage
Is it because it can exceed the reverse breakdown voltage of semiconductors?
For instance in low voltage devices say 1-5v is the reverse voltage rated a lot lower than that for damage to occur?
Also ...
1
vote
2answers
57 views
Why MOS transconductance is not zero even when drain current is constant?
I am trying to plot transconductance \$ g_m \$ of the MOSFET below when \$ V_{gs} \$ varies from 0 to 1.8V.
The schematic is below. The drain current is fixed to a constant DC value 1uA by a current ...
0
votes
1answer
27 views
Derivation of transcondutance gm using Taylor expansion
From the fist page of the lecture, there is a derivation of transconductance of MOSFET using Taylor expansion.
As seen from the picture bellow, drain current is a function of vGS, vDS and vBS.
iD is ...
3
votes
1answer
41 views
Will there be a capacitance in a wound coil?
A wound coil in general is a series LR circuit. If the coil has N turns, will there be a capacitance in between consecutive turns of the coil? If there is a capacitance, is it parallel to L and R or ...
0
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0answers
26 views
Resonant RC Series and deriving equivalent circuit
How is it that this is equivalent? Assuming all transients have died out.
vi = Vcos(omega*t)
The fake input was defined as:
\begin{equation}
v_{cp}^\sim = \frac{V_i}{1+j\omega_1RC} ...
0
votes
2answers
76 views
Analysis of circuit
Hi all,
So the question for this circuit was: Using logic gates design a circuit which turns on a light if any one of a car's four doors are opened.
Assume that each door is equipped with a switch ...
0
votes
2answers
40 views
Calculating true power of a predominantly inductive load?
I'm stuck at this problem, which doesn't seem to be so difficult, but, I guess there is some basic stuff that still confuses me. So, if we have a load represented with complex impedance \$Z=30+j40 \ ...
1
vote
0answers
32 views
I need to find the uppers and the lower bound of 3dB frequency
How can i find the upper and lower bound of 3dB frequency ??
I think I have to make first a small signal analysis including the capacitors Cgs,Cgd ..
0
votes
1answer
89 views
Small signal equivalent circuit BJT question
This circuit is two BJT transistors in so called 'darlington configuration'. I want to analyse this circuit for AC signals (where the capacitors are shorts).
The question is to calculate ...
-1
votes
1answer
47 views
Two-port circuit analysis. Voltage gain [closed]
I am trying to find the general equations for the voltage gain(Not sure if it is the write word for it). My textbook offers an derived equation but not the procedure. I would appreciate it if ...
0
votes
1answer
32 views
Asynchronous sequential circuits
How do I analyze a sequential asynchronous circuit? The yellow part is the one I don't get (I know how it works, but don't know how to write it when I do the analysis)
0
votes
2answers
39 views
KVL with multiple source
I am looking at the problem in page 5 of this document.
It is an example of KVL (Kirchoffs voltage law).
The circuit is as shown below -
.
I have 2 questions -
1) Why is the voltage -5V ? Is it ...
0
votes
1answer
34 views
Using KCL/KVL to derive differential equation of a mixed RLC-ciruit
I have the following LTI sinusoidal circuit, and I am trying to derive its differential equation using KCL and/or KVL. I need this to derive the Power Factor as function of the components, so I can ...
0
votes
1answer
41 views
ambiguous component values (ex. U01 U47 M47 etc.)
i'm having a hard time understanding components value when it's given in the following formate
U01
U47
M47
sometimes it's even worse like 4N7
i know that U for micro, M for mega, N for nano but i ...
1
vote
1answer
27 views
How to apply reciprocity theorem to h parameters? [on hold]
I know the result is h12 = -h21, but it's strange since h12 = V1/V2 and h21 = I2/I1.
Reciprocity theorem says that ratio of excitation to result must remain same if they are interchanged, how do you ...
0
votes
1answer
32 views
Getting the Wrong Transfer Function for Controls Problem
Background
So admittedly, it's been about 5 years since I've dealt with any kind of circuits and now I am going back and taking a controls course. On the very first problem I am doing, my answer is ...
0
votes
1answer
37 views
Understanding why voltage and current sources are to be divided by s in the frequency domain
I have been told that whenever I'm drawing a circuit in the frequency (s) domain, the voltage source is to be replaced by V/s and the current source by I/s.
But what exactly is the reason?
When I'm ...
1
vote
2answers
198 views
Which circuit best approximates a zener diode?
Above on the left side is the original zener diode circuit.
I want to draw an approximation of this circuit, given the zener voltage Vz and zener resistance Rz (Rz is considered constant for ...
0
votes
1answer
90 views
Solving a source free series RLC circuit
How do I proceed to solve this problem. If I write a KVL equation, I get
$$4 (4 Vc) +1/10^-3 integral i dt - 10=0$$
What to do next?
9
votes
3answers
818 views
Are there any quick way to tell if a filter is high-pass, low-pass, or band-pass, just by looking at the transfer function in the s domain?
How can I quicly determine if a given filter's transfer function like: \$ H(s)=\frac{k}{s^2+ks} \$, or \$H(s)=\frac{1}{s+k}\$, is either a low-pass, high-pass, or band-pass ?
2
votes
2answers
58 views
Closed circuit vs low resistance resistor
I'm learning electronics and this confused me.
In this circuit it shows that current flows through both wires with resistors and lower only through one wire where there's no resistor (even though one ...
0
votes
0answers
31 views
Finding the current through resistor in source free parallel RLC Circuit for t>0
My solution: Since alpha >w0, so response is overdamped.
Current through inductor:$$ Il(0-)=Il(0+)=6
$$Voltage across capacitor: $$Vc(0-)=Vc(0+)=0V$$
Current through resistor:
$$ Ir(t)=A1e^{s1t} + ...
0
votes
0answers
25 views
How LTC3108-1's oscillator work?
I am reading about LTC3108-1 on the page.
There is one part about oscillator that I am not sure how it works.
Could anyone explain it more detail? Or could you give me a link so I can read up?
...
0
votes
3answers
74 views
Using complex number in solving linear circuits
I am reviewing about using complex number in solving electrical linear circuits.
I see that the input sinusoidal signal \$ V_m \cdot \cos(\omega t) \$ is replaced \$ V_m \cdot e^{jwt}\$.
Then solve ...
0
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1answer
46 views
Building a magnetizer
I'm building a simple magnetizer for the realization of a physics experiment, bought yesterday components for the construction of the same, I am following the scheme of this site:
The final ...
0
votes
2answers
46 views
How were values of Vc(0+) and i(1.5ms) found?
I get that by applying source transformation, we get a (0.1*200=20 V) source but shouldn't 0.1 A current be divided into 50 ohm and 100 ohm resistance?
Also why i=0 at t=1.5ms?
0
votes
1answer
47 views
How was Vc(t) found in this source free RC circuit?
Shuldn't \$v_c(t)\$ be the same as \$10^4\space i_s\$ after \$t=0\$?
0
votes
1answer
40 views
Plot of Ic and Vbe function
The book page 12 show the plot of collector current Ic vs temperature at fixed Vbe =600mV.
With the equation: Ic = Is*e^(Vbe/VT).
Where Is = 10^-16A.
Vbe = 0.6V
VT = kT/q = -8.6173324×10−5*T ...
0
votes
1answer
48 views
Differential equation mixed RLC-circuit, C parallel to RL
I am having trouble finding the differential equation of a mixed RLC-circuit, where C is parallel to RL. It is a steady-state sinusoidal AC circuit. I need it to determine the Power Factor explicitly ...
0
votes
3answers
103 views
How was this equation for finding current written?
It doesn't make any sense because at \$t\gt 0\$ the two circuits are disconnected (the left and right portion).
How has \$25 i_x\over 20\$ been calculated?
1
vote
1answer
40 views
Ethernet driver Circuit
I've been working on Ethernet schematics, i noticed a network of capacitor and resistors present outside the RJ45 connector. For what reasons these passive components are used? I've attached the ...
0
votes
1answer
28 views
Calculate the parallel value of resistors at base of common emitter amplifier
I don't know if questions can be asked like this here but if they can I want this question. In an exam paper I saw a question to determine the parallel value of the R1 and R2 resistors in the image ...
0
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0answers
27 views
First order circuits
I need to find the analytical expressions of the voltage and current across the inductor. I have found the initial conditions in order to solve the differential equation:
v(0) = 0 V and i(0) = 5 A, ...
0
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2answers
45 views
How do I solve this electrical circuit?
The voltage across R is Vr. I want to plot I vs Vr on a graph.
Given I = 6k mA. Now, my question is this: wont I vary with varying V1? Did I copy something wrong, or is there a way to plot this?
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1answer
73 views
What is mean by short circuit voltage [closed]
What is mean by short circuit voltage in Electrical Engineering
3
votes
2answers
115 views
How is the current through resistor same as collector current in this circuit?
My textbook says that the current through resistor will be same as the collector current when the diode shown matches with the base-emitter diode internal to the transistor. Could somebody kindly ...
0
votes
0answers
23 views
Graphing a relation between input and output voltages in a circuit with 2 MOSFETs [duplicate]
simulate this circuit – Schematic created using CircuitLab
Sorry for the 'homework' post.
\$Vout=f(Vin), 0V < Vin < 3V, Vdd=3V, R=20k \Omega, \beta1=\beta2=10mA/V^2, Vtn=0.5V\$ And ...
0
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0answers
35 views
Graphing a relation between input and output voltage in a circuit with 2 MOSFETs
simulate this circuit – Schematic created using CircuitLab
Sorry for the 'homework' post.
\$Vout=f(Vin), 0V < Vin < 3V, Vdd=3V, R=20k \Omega, \beta1=\beta2=10mA/V^2, Vtn=0.5V\$ And ...
0
votes
2answers
56 views
How to make auto off functionality for an led lamp circuit with only transistor, capacitors, timer 555 chip?
The components I have are timer 555 chip, capacitors, and transitors. I want to create sleep functionality for a led lamp which consists of 6 leds in parallel and pnp, npn transistors.
I want this ...
0
votes
0answers
14 views
Circuit problems for pressure transducer
I am working on a circuit to amplify my output voltage from a pressure transducer with the range of events 3-20 mV to be ready by a national instrumentation DAQ USB 6008
I have worked on 2 circuits ...
4
votes
5answers
161 views
Can a Tesla coil's secondary wiring overlap?
I am building a small tesla coil just as a proof-of-concept using a bug-zapper circuit. I unwound some enamel copper wire off a transformer and put it on my 12 cm length x 2 cm diameter PVC pipe and ...
0
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1answer
60 views
How to measure micro and nano amps via microcontroller [closed]
The objective is to build/construct a circuit powered by an ATMEGA32 IC, using C++. This circuit will essentially be an ammeter for small current levels (10-6 and 10-9).
I've done some basic points ...
2
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2answers
63 views
Problem with short circuit
Comparing with short circuit how does a current flow in parallel circuits with different resistances. Shouldn't it just choose the one with lesser resistance?
0
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2answers
96 views
Why does my Kill-a-Watt read Power of only half the Voltage times Current?
My Kill-a-Watt is displaying that its output is 120 V, 0.16 A, and 10 W.
I'm confused... I thought P = V × I from basic EE. Why do I see only half the expected value here?
(This is a USB charger, ...
0
votes
2answers
67 views
One Digital Logic Question in Previous Exam?
I Prepare for Entrance Exam on PhD, CS Filed. I ran into a previous question with following options (A to D from one to forth lines):
The question is:
if the input is always has valid values (no ...
0
votes
1answer
46 views
Bridge circuit and the error caused by a differential amplifier
I am currently struggeling with solving the following problem: The circuit below shows a bridge circuit, where the differential voltage between the branches is measured by a differential amplifier. I ...
