Tagged Questions

1
vote
2answers
160 views

transfer function of active filters

I've been looking for some straightforward method or trick to obtain the transfer functions of active filters (like the Sallen-Key filter , the butterworth or Cauer topology etc...) since KCL or KVL ...
5
votes
5answers
204 views

How to recognize the type of analog filter given its topology?

Having trouble to tell what kind of filter (Low-Pass, High-Pass, Band-Pass, Band-Reject(Notch) are present given a topology in cascade. In the following picture I see 3 stages, is this ok? (2 active ...
4
votes
1answer
173 views

Differentiator Circuit

So I have a circuit like this: With the output equation as: \$ V_{out} = -(\frac{R_2}{R_1})\frac{s}{s+\frac{1}{R_1C}} V_{in} \$ So the question is to derive the time-domain equation in terms of the ...
2
votes
1answer
189 views

Sallen-Key filter problem

I am an Electrical Engineering student and I'm making a relay test for dad because I want to design stuff. Basically, there is an oscillator switching the relay constantly, and there is a \$ ...
8
votes
3answers
423 views

Audio Amplifier Op amp

I'm trying to design a circuit in which a microcontroller produces a signal and then using an amplifier drives an 8ohm speaker. I've so far used LM386, but it cannot go above 1W, which turned out to ...
0
votes
3answers
411 views

Using Mic from 10 feet away for voice recognition

I'm trying to use a mic from 10 feet away. Background: for my senior project I would like to talk to a computer to run scripts, but I want to talk to the mic throughout the house. So I need to be ...
10
votes
2answers
757 views

How to analyze this circuit in the time and frequency domain?

I came across this circuit in another post and started looking at the op amp filter and how to apply traditional circuit analysis ( using 1/jwc for capacitors) and couldn't derive the transfer ...
1
vote
5answers
798 views

IR Demodulator Design

I am designing an IR demodulator circuit to replace the one shown in this question. Basically I want to demodulate a simple IR signal modulated at 32.678 kHz. I just need to know if the signal is ...
2
votes
2answers
333 views

Detecting a 15KHz pulse with logic output

I want to build a simple and ultra low cost circuit that can detect a timed (let's say 200ms) pulse of a single sine frequency - say,15KHz. Amplitude will be around AC ~1Vp-p. Detection will give a ...
1
vote
3answers
696 views

What does the term “slow drift” mean?

Good night everyone. I came across the term "slow drift" when reading a paper on an electronic design, and I am not quite sure what it means. The author said he used a low pass amplifier to remove ...
1
vote
2answers
776 views

Amplifying and filtering a very low frequency signal(Bandwidth of 4Hz)

Good night, everyone. I want to amplify and filter a signal that has a bandwidth of 3.5Hz and is of the order of 5 - 40 milliVolts. I plan to amplify the signal before filtering it so as to prevent ...
9
votes
2answers
857 views

Twin-T Active Notch Filter Analysis

Could anyone give me a hint in analyzing the Twin-T Active Notch Filter? I tried a delta-star transform, followed by nodal analysis, but ended up with conflicting equations. For an example, look at ...
2
votes
2answers
426 views

Can I replace a PLL Charge Pump with an Active LPF?

Background I am using a MAX9382 phase frequency detector in a project. The application notes recommend using a charge pump on the output of the IC. In PLL applications there is an up and down line ...