This receiver uses old transistors that are equivalent to BC548 and BC558. The photo diode is of any type. The receiver can be used on a highly sensitive audio link.
MCP19124/5 Contains Independent Voltage and Current Control Loops Plus a Full Suite of...
This circuit is from an old documentation from the 70s, so the transistors used are not common....
This small transmitter can act as a wireless microphone operating in the medium wave range,...