Found in a 1968 Motorola publication, this circuit generates a high-powered audio tone when triggered. Equivalent transistors can be used.
We found this circuit in a 1976 documentation. The circuit uses a double gate MOSFET. The circuit...
We found this circuit in a Popular Electronics of the 90s. Its purpose is to detect when it locks...
Carbon microphones are no longer used in most projects. However, finding one in the scrap metal, it...