We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio amplifiers can be used. Transistors are commonly used.
This circuit provides a reference voltage of 2.5 V adjusted in the trimpot. The transistor can be...
This calibrated circuit was found in documentation from the 1980s. It makes use of an integrated circuit...
This circuit was found in a 1987 publication. A 4017 sequentially counts time in steps set by...