This interesting circuit found in American documentation generates a busy signal, without you having to take the phone off the hook if you do not want to answer. The components used are common.
The simple touch of the fingers on a sensor causes this circuit to drive a motor that goes into...
This simple circuit found in an American 80's documentation simply blames if there are toxic gases in...
This circuit is from Motorola's 1990 Linear Databook. The transistors allow equivalents and the...