In the figure we have a simple way to produce tone in a piezoelectric transducer. The frequency depends on the capacitors and the supply can be done with voltages from 1.5 to 6 V.
The time constant for this circuit found in a 1973 publication is given by R and C. The shot is...
This circuit adds the voltage from the secondary of a transformer to an outlet connected to the...
This two-transistor circuit was found in a 1966 US documentation. The power transistors are of the...