This circuit was obtained from an 80's Electronic Engineering. The circuit detects ice formation by triggering a warning light. The operational amplifier is of the time.
This circuit was obtained from an Auguist 1974 Everyday Electronics magazine. The circuit is still...
This sonic, sound or vox switch uses common SCR and transistors can be BC548 or equivalent. The...
The circuit shown in the figure is from a 1976 publication. Equivalent tunnel diodes can be used....