This circuit was found in an English publication from 1967. The circuit is for listening on a phone. Transistors are types of germanium of the time.
This small 3 transistor transmitter was found in an English publication from 1963. The coils must...
This optical pass-through shield can be used in various applications, such as object sensing or...
This circuit for light data transmission (visible or IR) has a maximum speed of 1 Mbps and can be...