This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This simple digital circuit tester can work with TTL technology when powered by 5 V and with CMOS...
This circuit generates 24 V positive from a 12 V supply. The maximum output is 1 A and the power...
This small power supply for low currents (5mA) is suitable for power low-power TTL experimental circuits....