We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio amplifiers can be used. Transistors are commonly used.
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...
The presented circuit was suggested by the 1994 Linear Applications Handbook from National...
This circuit was found in a Motorola documentation from 1968. The load current is 10 A. The...