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 1968 Mullard circuit detects fire by smoke using LDR-type sensors. The circuit makes use of...
Found in the American 73 magazine for radio amateurs, this circuit can test common quartz...
With this circuit it is possible to tune the signals in the 50 MHz band in a common AM receiver around...