We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio amplifiers can be used. Transistors are commonly used.
This small 2-transistor amplifier was found in the Radio Electronics magazine of May 1959. The...
When activated, this relay remains activated for a moment, generating a pulse in the load. The...
This tuner circuit was found in an old English documentation. The JFET can be any general purpose...