Found in a 1980s American documentation, this circuit uses programmable unijunction transistors of the time. The time interval obtained depends on the capacitors that can be changed.
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...