Linked Questions

20 votes
6 answers
5k views

I don't quite understand this FET-BJT preamp circuit

I see this circuit a lot on electret microphone preamps, but I don't quite understand it. The FET is operated as a common source amplifier, so it has gain, inverts, and has relatively high output ...
endolith's user avatar
  • 28.7k
5 votes
3 answers
12k views

Ground loop? Switch mode power supply noise

I have a single 12V supply powering a 12V class D audio amplifier (Tripath TA2020 based, model 'SMSL SA-36') (C) and a very cheap 12V to 5V 2A rated switch mode converter (A). The 5V is used to power ...
damian's user avatar
  • 343
5 votes
3 answers
11k views

How to read an audio signal using ATMega328?

I was trying to use the ATMega328 ADC port A0 to read a signal. The hardware I used was: Seeeduino Stalker Electronic Brick Shield Microphone Electronic Brick (I found a link to the original ...
Jader Dias's user avatar
  • 1,973
4 votes
1 answer
4k views

Simple Biasing Circuit

I'd like to formally understand this simple biasing circuit: Let V+ be the supply voltage, Vi be the input voltage at the seemingly unconnected terminal of the capacitor, and let Vo be the output ...
Gus's user avatar
  • 431
1 vote
3 answers
3k views

Controlling audio signal with digital potentiometer

I am very confused about how to go about using my digital potentiometer to control an audio signal. I have a MCP4231 digital pot and I would like to use it as a MCU controlled variable resistor for ...
Hooplator15's user avatar
0 votes
2 answers
4k views

AC voltage sensing circuit

In a project I'm working on, I am designing a Totem pole PFC, and for the controller (using a digital controller) I need to sens the input voltage, which is an ACvoltage and feed it to the ADC of the ...
Dark Mythos's user avatar
5 votes
2 answers
713 views

TI Application Report - What are those additional resistors in the low pass filter

I was searching some documents and tutorials online for filter design. Then I stumbled upon this TI application report. The following is referring to section 2, figure 7 and figure 8 of the paper. I ...
PetPaulsen's user avatar
  • 2,343
2 votes
1 answer
2k views

How can I vertically shift the voltage of a zero-centered signal such that I can read it with the Teensy 3.2's internal ADC? [duplicate]

I have a sinusoidal signal with a frequency of 100 kHz. It's zero centered with a peak-to-peak of around 3V (i.e. from -1.5V to +1.5V). I want to be able to read the peak-to-peak voltage with one of ...
rcsmth's user avatar
  • 23
1 vote
2 answers
1k views

cirrus/wolfson wm8731 - Connecting Analog Input to Codec

I am currently working on an embedded audio processor project based on the stm32f4discovery board and the wm8731 codec from cirrus/wolfson. I was wondering if anyone here is familiar with the codec ...
a_wahab's user avatar
  • 13
2 votes
2 answers
895 views

MCP4921 audio: removing output DC Bias

I've seen a number of posts out there concerning adding/removing DC biases, and I can't seem to find one that has been directly applicable to my problem. Question: How do I remove the 1.5V DC step ...
user2608147's user avatar
1 vote
3 answers
875 views

Audiable pops when switching DC biased audio signal

In my previous question, I have asked how to DC bias audio signal for a crosspoint audio switching matrix (Switch array (crosspoint) and DC biasing of audio signal). I am using the following circuit ...
Klemen's user avatar
  • 15
0 votes
1 answer
579 views

How to calculate cutoff frequency for a high pass filter in DC biasing circuit

I would like to DC bias an AC signal using a voltage divider as shown in the following schematic. I realise the bias point would be subject to noise from the power rails, but that is not a concern for ...
Pzy's user avatar
  • 357
0 votes
1 answer
415 views

bias a signal with DC input coupling, but without attenuation?

I want to bias the analog signal present on an MCU output pin. This signal varies between 0v and ≃3V, I need to shift it down to -/+1.5V range. Most importantly, I need to keep any DC offset ...
iRgKjFFCfb's user avatar