This heartbeat sensor circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit uses a 741 with a single power supply.
This circuit that can be activated by light or heat was found in an old American documentation, but the...
This old two-stage video amplifier uses integrated circuits that are not easily obtainable today. The...
We found this circuit in an Electronics Now magazine from June 1995. The transformer has a primary...