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Questions tagged [homework]

Use this tag if the question you are asking is an assignment or homework with which you require assistance. EE.SE is not a homework answering service, so make sure you show what you have attempted so far and are specific as to where you have gotten stuck.

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1answer
29 views

Overdrive Voltage Effect on Cascode Operation

Working on this exercise: I understand that if all the transistors in a cascode have the same current and the same Vgs then they will have the same Vov. However in this case the Vgs do not seem to be ...
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2answers
75 views

Which region is the transistor operating at?

PNP and NPN transistors in the circuit have identical Is values. Based on the PNP transistor is connected to a DC voltage source. k = 1.38064852×10-23 J/K qe = 1.60217662 ×10-19 C Is = 0.69 fA at 17°...
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0answers
24 views

Yagi-Uda antenna - energy flow density calculation

There are given two, identical, parallel, short dipoles perpendicular to the OX axis connecting their centers, located at a distance of λ / 4 and supplied with a phase shift of π / 2 (figure below). ...
0
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0answers
62 views

Exposing a 220v socket in my condo [migrated]

I live in the US and own a few appliances (mostly, audio) that are European, designed for 220V and don't have a built-in converter to deal with 110V. I'd like to find a way to use these in my condo, ...
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1answer
44 views

Calculate the capacitor voltage for t < 0 and t > 0 for the circuit below

Please help me calculate this. I tried using the thevenin equivalence method however I'm not familiar with two independent sources in a circuit. When I was simplifying using thevenin method the ...
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0answers
36 views

Parallel MOSFET Circuit Analysis

I'm solving part b of this question I started with the assumption that both MOSFETs were in saturation mode to simplify calculations, I then solved for the circuit, tested the assumption using vds, ...
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0answers
24 views

Quick help for Source Transformation Problem

I understand that I shouldn't ask for help on homework question, but I seem to be stuck on this one problem with a dependent source. All I need is a little hint so that I can complete the question. ...
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votes
2answers
80 views

PS/2 mouse / keyboard interface info and classification

My hardware interfaces teacher in the university gave a task to find info about PS/2 interface and fit it into a classification by answering a list of questions. Here's what I've found: Which type ...
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0answers
67 views

How to know Number of turns

In closed magnetic circuit, How many turns are when a conductor winded around a square mild steel core with permeability (Ur=2410)? The outer length is 20 cm and inner length is 16 cm. The current ...
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1answer
73 views

Kirchoff law exercise

I need to determine the current across the 4 ohm resistor (name it I1). What I calculated, thought out so far : Current of 2 ohm resistor : I=5V/2ohm=2,5A. I Think this current is flow towards the A ...
1
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1answer
86 views

electrical homework help

I need to solve exercise 57. I need to determine the voltage between points A and B in diagrams (a) and (b). What I think so ...
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0answers
66 views

Calculate V0 and I0

For my homework I have to find V0 and I0 in the following circuit, but I have no clue where to start.
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2answers
87 views

Common emitter amplifier gain with load resistor?

I have a problem I am working on where I have to find the voltage gain of the following circuit with a dc collector current of 0.3mA. My attempt at a solution involved using the formula A=-(RcIc)/Vt ...
2
votes
1answer
80 views

Fourier Series Expansion of the phase current of a three phase full wave bridge rectifier

I am really struggling with this homework problem where I am asked to calculate the harmonic components as a ratio of the first fundamental harmonic of the phase current of a three phase rectifier ...
3
votes
2answers
138 views

Output resistance of MOSFET circuit

I am trying to find the output resistance \$Rout\$ of this circuit consisting of 3 n-type MOSFETs. It is given that all 3 MOSFETs have \$g_m=4 mA/V^2\$ and output resistance \$R_o=100k\Omega\$. ...
1
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2answers
66 views

How to find v through superposition theorem in the following ciruit

What is the voltage V of the attached circuit? Using super position theorem. When i active the 9V source & short 12 V source is the current follows in 20 ohms, 10 ohms. & 4 ohms? Or it only ...
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2answers
109 views

How to Find R.M.S value [closed]

how can I find the R.M.S value of this question?
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1answer
68 views

Current biasing in npn transistors [closed]

I need to calculate bias current Ic1 and Ic2. I understand that both currents are the same and, because of beta being infinity, there is no base current (Ic1 = Ic2 = Ie1 = Ie2) and Ic3 = 2 * Ic1. I am ...
1
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2answers
87 views

Receiving power from antenna (Homework)

The question: "At a carrier frequency of 2 GHz, assuming a transmit antenna gain of 3 dBi and a receive antenna gain of 0 dBi, calculate the line-of-sight received power at a distance of 100 m from ...
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0answers
57 views

Logic-based light system

I need to develop a system that turns on the red light when all three switches are off, and turns on the orange light when any two out of three switches are off. The red light part is already sorted ...
1
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2answers
43 views

DC Black Box and Thenevin Equivalence

There's a DC Black Box, and my goal is find the Thevenin resistance within the black box. By connecting a digital mulitmeter to the terminal, I have found that the "open-circuit" output is \$0.647\ \...
0
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1answer
32 views

Double BJT circuit with one BJT off and one in saturation

In the circuit below, due to the base voltage, the circuit becomes a common-emitter setup. However, assuming a reasonable value for the base current the BJT should be in saturation. However the value ...
0
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1answer
79 views

How do you visualize the frequency spectrum for a digital waveform? [closed]

How does the mathematics of a single or periodic rectangular pulse help us quickly visualize the frequency spectrum for a digital waveform? Develop the ideas behind this. My professor posed this ...
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0answers
39 views

Symbol rate of the application

so I have this problem: "Data modem transfers information at the rate 56 kbps using 128 signalling states. What is the symbol rate of the application." I thought it is as simple as this: M = 128 = ...
1
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0answers
30 views

Determining the Impedance of the antenna on a known circuit

I am stuck on how to approach the following problem: I have a graph with both the response of a short-circuit and an unknown impedance antenna. The only information I have from this graph is the ...
2
votes
2answers
562 views

Combining resistors in a simple network

I'm trying to reduce this circuit into 1 resistor and the current source. The dots indicate nodes, which I'm not sure makes a difference... Can I combine R1, R2, and R3 in series, then, R4 and R5 in ...
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3answers
76 views

Triac Dimmer Supplying a Purely Inductive load

I was asked a question in my lab viva today, on a triac switch supplying a fixed value inductor of 0.2 henry. How will the current and voltage of the inductor vary, if the triac's firing angle was ...
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0answers
37 views

PV Device, IV chart approximations

I have this PV device and IV values shown. I am not sure if my thinking is correct for the following problems. Over what range of voltages can I approximate a ideal current? I thought that it would ...
0
votes
1answer
58 views

Equivalent noise resistance(s) - 2 stage amplifier

I came across this question in my textbook: The first stage of a 2-stage amplifier has a voltage gain of \$150\$, an input resistance of \$1500 \Omega\$, an equivalent noise resistance of \$700 ...
0
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2answers
43 views

Signals and Systems - Taking Integral of Unit Step Function

I am a taking signals and systems course and my professor posted the solutions to our latest homework and I am trying to understand one of the steps. Below is the solution. Bracketed in red is what I ...
0
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0answers
23 views

What is the maximum number of natural frequencies given circuit elements?

I'm learning forced and natural responses, as an exercise the textbook gave 4 scenarios (2R&C, R&2C, 3R&2L, and 2R&C&L) and asked what the largest number of natural frequencies for ...
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3answers
98 views

What value of C should be added in parallel to make the circuit appear purely resistive?

I'm currently working through Cogdell's Foundations of Electrical Circuits and came across problem 4.39 d) as shown below: Earlier in the question I found the frequency-to-be-used as 43.3x10^3 rad/s. ...
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0answers
29 views

Impedance Expression for a Transmission Line

I'm studying transmission line theory and this is the expression I derived for the input impedance for a lossless transmission line: $$ Z(\omega) = Z_{\inf} \frac{1+e^{i\frac{\pi\omega}{\omega_{0}}}}{...
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0answers
149 views

Capacitance of a particular transmission line

Is it possible to derive the expressione of the equivalent capacitance seen by AB for this kind of transmission line, where w is the width of the wire, d the spacing, l the length of the repeated part ...
1
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1answer
37 views

Norton equivalent circuit question

I'm unable to get the correct result for this question. I've tried using ohm's law like this: 30 = INRTh I'm not sure if the current through the shorted branch ab would be the same as the current ...
0
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1answer
6k views

Design a 3-Bit Up Synchronous Counter Using JK Flip Flop (odd vs even numbers)

I have to design 3-Bit Up Synchronous Counter Using JK Flip Flop counters. The first one should count even numbers: 0-2-4-6-0 The second one should count odd ...
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0answers
22 views

CSxCC stage, series-shunt feedback, identify sign of feedback

MY ANALISIS The stage is inverting x non inverting = non inverting. Shunt sampling since it perturbs the output current, Series mixing. Thus if a positive input voltage is applied, the output is ...
0
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1answer
31 views

Determine transconductance of a JFET given only voltage gain and internal drain resistance

I have a homework question as follows: If a JFET having a specified value of rd=100 kΩ has an ideal voltage gain of Av(FET) = -200, what is the value of gm ? As far as I know, the closest formula for ...
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0answers
38 views

Brune test in a parallel-parallel two-port network connection

Alright, so I am struggling so much with this problem that I am solving, since to my mind this specific example is a bit more challenging to other two-port network problems that I have solved. The ...
1
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0answers
56 views

Help with JFET circuit analysis

Just having trouble analysing the following circuit with the information given. where k=0.16mA/volt^2, Vt = -1.7V and A = 1V. I believe you have to first find an expression for V_gs but the ...
0
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1answer
48 views

Thévenin equivalent of a Norton equivalent

A very simple question. When solving circuits, and you need to solve it using the mesh analysis, you want the circuit to only have voltage generators.I wonder if for an independent current generator ...
-2
votes
1answer
29 views

Match the corresponding equation to the RC circuit

By trial and error, I have found that the equation for circuit 1 is the second equation listed. Can someone please take the time to explain this to me. I have been working to "combine" the circuit ...
0
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1answer
95 views

Equivalent R for Bandwidth of non-ideal parallel RLC circuit

I'm tasked with calculating the bandwidth of a tank circuit shown below. I can see that it is essentially a parallel RLC, for which I know BW=1/RC However that ...
-2
votes
3answers
115 views

How to trigger a pulse until a capacitor fully discharges based on the output of a comparator

In my circuit I have a comparator which compares the output of a sine wave with a staircase wave, if the staircase is above the sine wave, I wish to use a Mosfet in its cut off mode which will allow ...
0
votes
1answer
102 views

Kirchoff's Law Loop Equation Problem

This is the question I am struggling with I have found a node equation: $$ I_3 = I_1 + I_2 $$ I have found two loop equations: $$ 50 = I_3 + R_1 \times I_1 $$ $$ 50 = I_3 + R_2 \times I_2 $$ I'...
0
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1answer
38 views

Should I consider systems to be causal or non-causal by default in questions like these?

Could anyone explain to me when to consider one-sided Fourier transform and when to consider two-sided Fourier transform? Normally in a question, just an input signal is mentioned, without stating ...
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2answers
118 views

Thevenin equivalent circuit with external loop

I am tasked with the following exercise: I am still finding Thevenin equivalent circuits challenging, and this example looks a bit daunting since it seems to have an external loop. Hopefully, I ...
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0answers
87 views

How to deal with low pass filter questions if Fourier transform of signal does not exist?

I found this question in a previous test paper: I'm having a few confusions: 1) Low pass filters are supposed to block signals below a certain frequency. Here that certain frequency is \$w_c=a\$. I'...
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0answers
81 views

Coherent FSK Modulation correlation coefficient derivation

FSK has a large bandwidth requirement and its minimum bandwidth is around \$4 B_T\$, where \$ B_T \$ is the bit rate. In a coherent FSK system the signals \$s_1(t)\$ and \$s_2(t)\$ representing bit ...
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0answers
85 views

Is it okay to write KVL equations like this (using complex numbers)?

For the circuit shown in the figure, determine the value of \$V_2\$ such that current through \$5\Omega\$ resistance is \$0\$. My attempt: Let current in left loop be \$I_1\$, middle loop be \$I_2\...