Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network.
3
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1answer
71 views
Not sure how to find current
Here's a circuit:
As you see there's a dependant source, 0.01Vx, depending on Vx, the voltage at the resistor of 150 ohm.
I don't exactly know how to handle this circuit properly. The presence of ...
0
votes
1answer
65 views
Nodal analysis in simple circuit
I have a circuit to solve:
In this approach, I inferred the V1 from the parallel connection of voltage source. For the second node, I have applied the KCL.
I also tried to do it another way, by ...
2
votes
1answer
49 views
RC Circuit response to different input voltages
For an RC time constant circuit like below, what is the behavior of the circuit for different inputs:
A Linearly rising input.
A repeating Sine wave
Square wave
Based on the values I do ...
0
votes
0answers
49 views
Voltage divider circuit pnp transistor
From the above circuit I wanted to know
If the switch is in position 2, will the 100kΩ resistor be parallelt to the resistor R?
Is the power dissipated by the transistor equal to Vce*IC
2
votes
1answer
63 views
Linear Transformer and Ideal Transformer: electric circuit question
The question is to determine k in so that no current flows in Zx. I literally have no clue how to start. If there is no current in \$Z_x\$ that would make it an open circuit, so for it to be ...
2
votes
3answers
73 views
Steady State RLC Circuit With Dependent Current source
I'm trying to figure out the reason why in the following circuit, at steady state, the current ix is zero. My best guess is that because there is a parallel branch which by KCL should equal 100ix and ...
0
votes
1answer
56 views
Ideal inductor in series with a resistor:
The question is to find the thevenin equivalent circuit across a and b. The inductors are ideal transformers. I stretched the inductors 180 degrees to make the circuit easier to analyze. From ...
1
vote
1answer
75 views
Basic electric Circuit with inductors
Its required to find \$v_o\$. The question should be easy but I am not getting the same answer as offered by the textbook which is 2cos(400t-53). I am getting 5cos(400t-53). I tried doing in two ...
12
votes
3answers
371 views
How do Circuit Simulators actually work?
I recently had the opportunity to play around with LiveWire, which is a circuit simulator and began wondering how exactly they computed the voltages across each component and the current going through ...
0
votes
1answer
30 views
DC LR circuit with current source
I'm doing a homework problem, and I think I've made some progress, but I'm starting to get confused and was wondering if somebody could help out with the next steps, the problem is below
So for ...
0
votes
3answers
78 views
Nodal analysis with two voltage sources
EDIT: I am not removing the linked question and redoing the question.
How do you formulate an equation on a node with two voltage sources connected in it, regardless if it is a supernode or not?
...
0
votes
1answer
34 views
Calculating feedback factor \$V_f/I_o\$
I'm unsure how to calcuate the feedback factor here. It's a voltage / current, so it's a resistor value, but what do you do when the values aren't from the same source? ie. it's \$V_f\$ and \$I_o\$
...
1
vote
1answer
80 views
Nano Electric Receiver Switch - Circuit Components
I want to recreate the circuit board below, but I am having a hard time figuring out what components I need. I have been trying to look them up on mouser but I haven't got any results.
It is called ...
4
votes
5answers
224 views
What is the most economical way to drive an array of single coil latching relays?
Please read the question to the end. The answer to this question may be non-trivial.
Replacing a number of 2-coil latching relays with single coil latching relays ...
1
vote
4answers
143 views
Current flow in a series circuit with two voltage sources
I specifically want to know how does the current flow in the schematic attached. There are two voltage sources (one dependent, the other independent) in the figure. Correct me if I'm wrong, but it ...
0
votes
1answer
54 views
Should I use Mathematica to understand circuit behavior? [closed]
I've just started learning about circuits from the "Foundations of Analog and Digital Electronic Circuits" book. KCL, KVL, element laws and linear circuits were easy to grasp but then I got the ...
4
votes
2answers
140 views
Problem modelling NPN transistor BE junction in LTSpice
So, I am trying to understand transistors.
I start with the very basics, the part which says that an NPN
transistor kinda look like two diodes joined at the hip (at the
anode, in fact)
I build the ...
0
votes
0answers
58 views
How to analyze circuits using frequency domain
Part 1
\$ u_1(t) = 141 \cos(314t) \$
Find \$ u_{LR}(t)\$ and \$ u_C(t)\$.
Here I thought we can transform this circuit into the frequency domain as:
where \$ \widehat{U}\$ means phasor.
\$ ...
-2
votes
1answer
100 views
How does an inductor generate back emf equal to a source driving it?
I have a question about the way inductors fundamentally work. How can an inductor be modeled as accurately as possible?
I tried to approach this problem from the basics of electromagnetic fields, but ...
1
vote
3answers
129 views
What mechanism happens inside an inductor from the point when potential difference is applied?
What happens when a potential difference is applied across an inductor? I am trying to get a picture of mechanism from start, just after potential difference is applied in detail? In resistor we can ...
2
votes
2answers
74 views
Op-amp analysis with capacitor
I have the next exercise:
I proceed as follows (assuming ideal op-amp):
$$C = 2 \mu F$$
$$R_{1} = 50k \Omega$$
$$R_{2}=10k \Omega$$
$$v_{2} = 0V$$
For \$t>0\$:
Node \$v1\$:
$$i_{s}=C ...
1
vote
1answer
73 views
Thevenin's Theorem for the circuit with controlled voltage source
We have a circuit like this:
The task is to transform it with the use of Thevenin's Theorem to a circuit like this:
I got the voltage \$U_i\$ by using the node voltage method, but I don't know, ...
0
votes
1answer
69 views
Equivalent circuit of resistor in parallel with inductor [closed]
Anyone know where the value 120 + 240j comes from? This is a resistor in parallel with 300Ω inductor.
1
vote
1answer
89 views
Transient analysis error(missing value) with OrCAD PSPICE 9.1
I am new to PSPICE, and just tried an example given in the book I'm using (SPICE by Sedra/Roberts).
...
1
vote
1answer
57 views
How to use Recom's R-785-0.5 switching DC-DC converters properly?
For my "prolonging life of old batteries" project I decided to try a switching DC-DC converter. I've got a couple of Recom's R-7805s (datasheet: ...
1
vote
2answers
67 views
Effect of time on a node with a capacitor
I have the next problem: Determine \$v_{0}\$ for \$t>0\$ where \$v_{s} = 20mV\$ in the next op amp circuit:
I proceed as follows:
At \$t<0\$:
\$v_{s}\$ is unplugged and the rest of circuit ...
1
vote
2answers
72 views
Thevenin voltage across current source
I got a weird question in a circuits analysis test today that asked for the thevenin equivalent across a current source and not a load. Is it valid to ask for the thevenin equivalent across a current ...
5
votes
4answers
247 views
Fundamentally knowing when to use capacitors / inductors [duplicate]
I've always stumbled when looking at even simple circuits that use capacitors or inductors and trying to work out why it is there, without using "past experience".
What I mean is, if we need to limit ...
0
votes
2answers
122 views
Why does the voltage across the speaker oscillate in this circuit?
For my final exam, I decided to work on this circuit design available online. Sorry, I forgot the website. No credit is due to me.
When I simulated this over at MultiSim 11, the voltage across the ...
1
vote
2answers
55 views
BJT in saturation, a circuit analysis question. how to approach question like that?
there is a question I cant solve.
I know that \$\beta\ =50\$ and \$V_{ce}\ (sat)\$ \$ =0.2 \$
I need to find the value of \$ V1 \$ that the BJT is in saturation
I've tried some KVL/KCL equation ...
1
vote
2answers
109 views
Equivalent Resistance in a short circuit
Find the equivalent resistance across terminals a and c. I don't know how the current flows in this circuit so I can't find the equivalent resistance.
12
votes
2answers
218 views
Under what conditions is the star-mesh transform invertible?
We all know and love the Δ-Y (delta-wye) and Y-Δ (wye-delta) transforms for simplifying three-resistor networks:
Image from Creative Commons
The Δ-Y and Y-Δ transforms have the nice property that ...
0
votes
2answers
70 views
Determining the equivalent resistance
It is required to find R=V/I given that \$V_{gd}\$ is zero.
Honestly, I don't know where to start. I don't think there is a current in the \$R_s\$ and \$R_g\$ resistors because the current has no ...
1
vote
2answers
70 views
Determining voltage and current in a circuit
The question asks to determine V_x and I_y.
I tried to find it by using KVL in to lower LHS mesh and KCL in the middle node. But, my final value is a contradictory statement(such as I_x equal all ...
2
votes
1answer
750 views
How to derive the resonant frequency from the RLC circuit?
Just like the title, i have an AC circuit (RLC) RL in series and they are in parallel with C.
How do I derive the resonant frequency from that circuit? It says to derive from first principles. I got ...
4
votes
2answers
181 views
Finding current using Kirchoff Law, but getting unsolvable system
Hello, the original circuit above is where I am trying to find I1, and I simplify it the figure below and assuming the following current directions.
Using ...
2
votes
2answers
119 views
Nodal Analysis algebra simplification
I am doing part a in this homework:
Doing nodal analysis of two op amps and came to these two equations:
$$\frac{V_1-V_{ref}}{R_2} + \frac{V_1-V_{x}}{R_1} + \frac{V_1-V_{2}}{R_f} = 0 $$
$$ ...
2
votes
1answer
82 views
Derivation of I_d of a self-biased JFET
I find that derivations of formulas are a lot more useful to me than just recitations of formulas. I'm looking at a self-biased JFET circuit, and I'm interested in deriving the quiescent state of the ...
4
votes
2answers
146 views
Does the NOT gate count towards the depth of a circuit?
So I was going through some problems for a course that I am taking this semester and I came upon a problem that seemed to imply something. Let me first say that I am not looking for the solution to ...
0
votes
1answer
169 views
Why is there a voltage drop across the load resistor in an ideal diode clamper circuit?
Consider a clamper circuit with an ideal diode, a capacitor, a load resistor and an AC input supply. When diode is in forward bias configuration, it must conduct and behave like a short. We must then ...
1
vote
1answer
89 views
In complex power and power factor analysis, how do I get the Thevenin impedance if there is a dependent source?
I'm preparing for my exam tomorrow, and I've found something ambiguous. How do I get the Thevenin impedance for this circuit?
Is it possible for me to get the impedance of the dependent source and ...
0
votes
0answers
66 views
Input admittance of circuit with independent source
For the above circuit. Find
$$ Y_{in}(s) $$ in frequency domain.
I'm thinking that the source doesn't play a role in determining the input admittance (?). So based on that...
So on the left we ...
4
votes
4answers
99 views
Replacing resistors with equivalent resistor
This is somewhat a homework assignment, but please bear with me. Given the following schematic, I want to know the overall resistance when measured from node A to node B.
simulate this circuit ...
2
votes
1answer
211 views
Realizing logic gates with transistors: AND and OR gate in parallel, trying to understand different behaviours
I am trying to understand and finally realize a logic gate by using transitors. In order to build a "simple" one-bit adder, my first step was to design a circuit that puts an AND-gate and an OR-gate ...
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votes
1answer
94 views
A question from Sedra/Smith Microelectronics
Hi, regarding question 1.12 in the pic.
I do get the first two answers, but I don't get the other answers.
So wev'e got: \$ V_L = 10\mu V_{rms} , \ P_L= 10^{-11} W \$
I know that we have: \$v_o = ...
3
votes
2answers
276 views
Zener Noise Generator - NPN BJT Amplifier Analysis
I'm interested in creating a low voltage white noise generator by means of a zener diode, as detailed here: Zener & BJT Noise Generator. Specifically, I want to use the circuit here, in order to ...
0
votes
0answers
49 views
Altium Simulation Node Voltages
When simulating a circuit in Altium it generates signals based on the components and net labels placed in the circuit, eg:
r1[i]
r1[p]
v1
v2
Altium also adds the ...
4
votes
6answers
355 views
Voltage drop assumption on diodes (LEDs, etc.)
I've always wondered why is it valid to assume some voltage drop (different from the junction voltage drop) on diodes or LEDs from the power up of a circuit. It simplifies the analysis, but it's ...
7
votes
1answer
381 views
How is this 5-24V input circuit working?
Since I require some kind of wide range input (going to a microcontroller) for a new project, I looked through some designs that are already in use (or were considered at some point) for other ...
4
votes
3answers
171 views
No output being measured on transimpedance amplifier
I have been playing with a SFH 213 photodiode (the clear one) and I've hooked it up to a TLV2371 op amp so as to resemble an ordinary transimpedance amplifier.
I've varied the feedback resistor ...
