This circuit also detects IR, providing LED indication. The circuit is used to indicate humidity in bench tests. We found it in the Radio Electronics magazine of February 1990.
This 1988 documentation circuit includes a charger and an inverter to power a small fluorescent lamp. The...
This circuit can act as a receiver for the transmitter of the previous circuit. We found it in...
The power source shown for powering for small TTL circuits was found on a Radio Electronics...