This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio Electronics from May 1963. The indication is by an analog instrument.
This circuit was obtained in an old American documentation, remembering that the 566 is the double...
At each touch of the sensor this counter based on circuit 4017 advances one LED. The circuit can be...
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...