Found in an Electronic Design of 1964, this circuit operates with control voltages from 0 to 12 V determining the duration of the pulses.
Carbon microphones are no longer used in most projects. However, finding one in the scrap metal, it...
This circuit produces a strong tone of audio or ultrasound, depending on the values of components C1 and...
This alarm from an old 1978 publication uses PNP transistors and driver and output transformers that are...