This approach alarm circuit was found in the September 1970 Radio Electronics issue. The 1 mH coil is wound on a ferrite rod. The relay is 12 V sensitive.
This circuit behaves like a capacitor whose value is C1 multiplied by the relationship between R1 and...
This circuit of an old 1968 magazine aims to synchronize a slide projector with a recording, but...
This switching power supply was found in an Electronic Design from the 90s. The components are...