This circuit emits a warning sound when night falls. The circuit is from a Hands On Electronics from the 90s. The Sensor is a common LDR and R6 adjusts the trigger point.
Found in American documentation from 1968 this circuit is based on discrete components in addition...
This circuit consists of a small inverter that can generate a few hundred volts of DC voltage...
This wideband circuit with the 4046 PLL was found in the December 1989 Radio Electronics magazine. The...