This 4093 IC continuity tester was found in the November 1986 Radio Electronics magazine. The circuit powers a ceramic buzzer with a frequency setting.
This circuit can be used to receive signals from CB18636E and other modulated light transmitters in this...
Due to its low working voltage, this circuit of an old EDN can be associated with a...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548...