We found these circuits in a Popular Electronics from the 90s. The circuit has a simple low power version and a higher power version with MOSFET (VMOS) of the time.
This fish flame circuit was found in a 1971 magazine. The circuit can still be mounted with BC558...
This circuit multiplies the input voltage by 3 and can work with up to 12 V input. The current is a few...
This heartbeat sensor circuit was found in the July 1992 issue of Radio Electronics magazine. The...