This bargraph circuit is from an ancient American documentation. It indicates the charge state of a set of 4 batteries from 9.6 to 5.2 V.
The current of this source is 200 mA at the most, and the output depends on the zener that may...
Found in a 1980s documentation, this circuit uses as base a component of the era. The formula for...
This guitar sustain circuit uses only two transistors and can be powered by a 9V battery. The...