This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
This 1965 Philips circuit uses old company transistors like the BFY51 and BFY50. The circuit is...
This circuit is from an April 1991 Radio Electronics magazine. The circuit uses power MOSFETs and...
This small power supply for low currents (5mA) is suitable for power low-power TTL experimental circuits....