This circuit, to add the ambience effect, was suggested by National Semiconductor in documentation from the 90s. The amplifier needs an appropriate power source.
This heartbeat sensor circuit was found in the July 1992 issue of Radio Electronics magazine. The...
We found this circuit in the 1982 SGS integrated circuit manual. The integrated circuit is not...
This TTL pulse stretcher or stretcher was found in a 90's EDN. The time constant R x C1 determines...