This circuit uses an 8 Ohm speaker as a microphone and has a very high gain amplifier configuration. The listener will be able to hear faint sounds using a standard pair of headphones.
It has been designed to perform optimally within the vocal frequency range, ideal for spying and surveliance.
It makes a great project to learn more about frequency filters, signal amplification, and using speakers as microphones.
This kit is a DIY kit and requires knowledge of how to solder.
Kit doesn't include:
About This Design
This circuit was designed by John S. Wilson Jr. and he reserves all rights to it. This design may NOT be reproduced or republished without his consent.
You can learn more about this amazing engineer on his website, http://www.bugplan.com/page1.htm.
You can find this circuit and Mr. Wilson's description of it on his website at http://www.bugplan.com/aa5.htm.