This circuit for monitoring telegraphy transmissions was found in a 1975 CQ magazine. Transistors may be modern equivalents.
This circuit for light data transmission (visible or IR) has a maximum speed of 1 Mbps and can be...
This transmitter was found in an old publication on espionage. It applies a signal of a few...
The circuit presented emulates an OR gate with the LM3900, operational transconductance amplifier....