# Tagged Questions

Questions attempting to analyze the mathematical properties of a formula, the inner workings of a protocol, or the design of a given circuit.

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### Puzzled by Nyquist frequency

Say I have a 1kHz sine, so no higher harmonics, then I need to sample it at least at 2kHz to be able to reconstruct it. But if I sample at 2kHz, but all my samples are on the zero-crossing, then my ...
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### Differentiating between a square wave or sawtooth wave with a circuit…?

I want to build a simple sensor that takes a 100 kHz square or sawtooth wave with a known amplitude and outputs a high if it receives a square wave or a low for sawtooth. I'm pretty sure this ...
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### Why does this circuit oscillate?

The circuit below is an oscillator. When I simulate it with ltspice, it does indeed generate a waveform (although it doesn't seem to be a very pure sine wave). What I fail to understand is why it ...
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### What's the difference between MOSFETs and BJTs (from a circuit analysis perspective)?

When analyzing circuits with transistors in them, when does it make a difference whether they are MOSFETs or BJTs?
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### How to analyze this diode circuit?

I am trying to analyze this simple diode circuit by hand, but I can't seem to get too far. simulate this circuit – Schematic created using CircuitLab Using circuit lab, it is evident ...
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### Predicting thermal equilibrium: what's wrong with my time constant?

I understand that this is arguably a peripheral electronics problem, but it seemed to fit here better than in physics. I've been doing some power electronics design work with large IGBTs mounted on ...
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Disclaimer: I am a beginner. I am reading a knol book on electronics, and I am faced with this schematics: How do I read a circuit to understand what it does ? Do I have to imagine the electrons ...
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### Proper assignations of current directions

What is the best way to know the proper direction of current? Lets say we have this circuit below: The correct directions are given below: What are your techniques to know which is the proper ...
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### Voltage divider ambiguity

considering the following circuit : ...
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### Circuit Analysis Shortcuts

I am slowly learning how to analyze circuits but I am wondering if my goals are unrealistic. My main reason is to help me repair circuits boards that I come across in my line of work. (I repair ...
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### Time-series Statistical Analysis with FPGA

Suppose I have two time series, such as stock valuations or radioactive diagnosis, for which I need things such as covariances (QP -problem) among other things. Covariance calculations should be easy ...
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### Frequency response - finding transfer function

I have a this circuit: I am asked to find |H($\omega$)| in its simplest form. I approached the problem by first recognizing that the first op am was a standard inverter. With that I basically ...
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### Circuit analysis - software?

Surely there is some software that lets you draw a simple circuit diagram (DC voltage source and resistors) and then tell you the voltage, current, resistance, and power on R1, R2, R3, etc as well as ...
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I am reading up on Thevenin's Theorem and this has prompted a few questions that I hope somebody will be able to answer. This is the tutorial I am reading. The circuit below is then given as an ...
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### Simulation for a transmission loop using PowerWorld

I am now learning how to use PowerWorld Simulator. However, I faced some problems when I tried to enter the data given in the paper. I want to simulate the following transmission loop: First things ...
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### Under what circumstances can impedances be simplified to simple resistances?

Consider the following circuit: This is a simple first-order low-pass RC filter. The cutoff frequency is: $f_c = \dfrac{1}{2 \pi (1k\Omega) (1\mu F)} \approx 159 Hz$ The reactance of C1 at ...
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### Sniffing USB traffic at the hardware level

I've been looking to purchase a USB sniffer that will parse packets at the hardware level. I've used usbsnoopy and the like, but a filter driver solution is not my ...
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### Calculating an R-RC circuit

This is not homework. I have this circuit, and I want to calculate V2. I know it is equal to V1 at t=0, and equal to $V1 \cdot \frac{R2}{R1+R2}$ at t=$\infty$, but I don't know how to calculate ...
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### Calculating Voltage

I am trying to calculate the voltage $Vw$ of the following circuit: I have little experience with these kind of problems, so I tried to solve first a more simple circuit that did not include the ...
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### Circuit short circuit capacitor question confusion

I am really unsure about how to go about this question and which circuits to consider. Here's the question: Determine the value of the current labeled $i$ and the voltage labeled $v$ at ...
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### Identifying an irreducible circuit?

How would you go about identifying an irreducible circuit? By irreducible, I mean combining resistors whether in series or in parallel to reduce the circuit.
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### How to calculate equivalent resistance?

This is not homework. Imagine an infinite resistor grid which the picture shows a part of. The question is what's the resistance measured across any of the 1k$\Omega$ resistors. I don't want ...
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### How to get fundamental frequency of a signal using autocorrelation?

I am trying to get the fundamental frequency of a signal that only has a single pitch. I coded out the autocorrelation function using FFT and already got the autocorrelation result. Unfortunately, I ...
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### Nodal analysis for current controlled current source

Okay here I go. I just started learning nodal analysis technique but I feel its difficult in solving the circuits consisting of dependent current and voltage sources. Im unable to solve this circuit. ...
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### How to solve a transient circuit

Given this circuit considering that before the switch closes the network is in a steady state. What steps should one follow to trace $V_{L1}$ before and after the closing of the circuit ? As far ...
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I have the following circuit I am having some trouble determining the relationships between Iac, Io and Iacpk. I'm not quite seeing how the final equation for Iac was determined, specifically ...
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### How do I treat a PMOS compared to an NMOS in small-signal analysis?

What exhaustive list can I use to determine the differences between NMOS and PMOS devices when doing small-signal analysis? Equivalently, what are the fundamental differences between NMOS and PMOS ...
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### Supermesh Analysis of circuit of two loops

I have am having trouble moving forward with the following problem. The problem says that Find the value of Vs in the circuit below such that the power supplied by the current source is 0. The final ...
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### Analyzing the Protocol

I am trying to understand a protocol (shown in figure 1) . For now this I have understood that data is transferred at high to low clock. as shown in figure. and the sync is for every 8-bit. But then ...
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### Common gate amplifier with load connected to negative DC bias

What's the difference between the following two circuits? Note that the capacitors are DC blocking, and the FET is on. I understand that usually, the load is connected to ground. But what would ...
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I'm trying to answer following question: In the ladder circuit in figure 3, find the current, I, if $V_s = 7V$. Use the fact that the circuit is linear. This can be done by assuming that ...
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### How do I deal with square, cubic, etc. zeros and poles when manually drawing a Bode Plot?

I'm manually drawing a straight-line Bode magnitude plot. Say, I have the following transfer function in standard form for a Bode plot: $$T(j\omega) = \frac{1+j\omega/10}{(1+j\omega/50)^2}$$ ...