Found in an Electronic Design of 1964 this circuit has a control for the frequency and another for the active cycle the signal. The bipolar transistor can be a general-purpose type.
This circuit was found in an Electronics Now of 1988. The circuit is still current, and the power...
With this name, we found this electronic stethoscope with a coal microphone in a 1957 Raytheon...
This transistor amplifier with complementary symmetry configuration can provide approximately 1 W...