This circuit was found in the July 1992 Radio Electronics magazine. Sensitivity adjustment is made at R6. Supply voltage is matched to that of the relay.
The transistor in this circuit can be the BC558 and the capacitors must be ceramic. Crystals from...
In the figure we have the basic configuration for interfacing TTL logic with CMOS logic. The...
This circuit includes a battery charging system and an inverter for operating a fluorescent lamp....