This simple digital circuit tester can work with TTL technology when powered by 5 V and with CMOS when powered by voltages from 3 to 15 V. The circuit provides LED indications and uses current ICs.
This common circuit is from September 1984 Radio Electronics. The transistors are general purpose, and...
This circuit is from a 1979 publication, using displays of 7 segments of common cathode. The...
This circuit is from a 1995 technical documentation. The transistor can be a BC558 and the sensor...