This circuit was found in Motorola documentation from the 1980s. The components are of the time, not currently common as operational and opto receiver.
I found this circuit in a Lujy 1962 English magazine. The circuit is still viable by simply using a...
Instead of the lamps, LEDs can be used in series with 470 ohm resistors. The circuit is from an...
Suggested by a Popular Electronics, this small amplifier that has a detector to follow RF...