Electrets Don't Work

I am having a problem making electrets work in various circuits I’ve taken from Charles Platt”s “Make: More Electronics,” 2016. The simplest is on page 59. It connects an electret to ground on a breadboard, and also to a 4.7K resistor. The latter is attached to the positive bus. I then measure AC volts between ground and a point between the electret and the resistor. I first tried using this brand: HiLetgo 10pcs Electret Condenser Microphone 52dB MP3 Microphone Accessories 6x2.2mm, which I got from Amazon. The first of these electrets worked the first couple of times I spoke aloud to test it, then didn’t work. The next couple of electrets were the same, so I sent them all back. I then got, also from Amazon, this brand: BOJACK 9767 Cylindrical Electret Microphone 2 Pins 9.7 x 6.7 mm Microphone for Intelligent Robot (Pack of 10 Pcs), which hasn’t worked at all. The book says to measure AC voltage both before, and while, speaking aloud. I should register, the book says, .1 (point one) millivolts before speaking and 10-20 mV while speaking. I have gotten a stable reading (about 5 mV with the first brand and 9 mV with the second) before speaking. With the first brand I got a higher reading when I spoke, but the readout varied quickly. I think it was maybe 2-3 volts. With the second brand I get no increase at all. It seems doubtful that both brands would be defective and, rather, that I’m somehow getting the procedure wrong. I’d be grateful for any opinions.

by swetstein2
June 05, 2022

You have the datasheet for the electret(s) that you use? Some are very basic, some include an opAmp IC built in, some operates at 1.5V, other at 10V, so they don't all behave the same.

Without seeing the datasheet, I would presume that your circuit killed the component(s) from over power (voltage time amperage) consideration, or by destruction of the capacitor internal insulation.

by vanderghast
June 08, 2022

1 Answer

Answer by swetstein2

Thank you for your response.

+1 vote
by swetstein2
June 08, 2022

Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account

Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers

Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.

About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.