This 1974 circuit uses two 555 integrated circuits in a very traditional configuration. The circuit can be powered by voltages from 9 to 12 V and for greater volume an amplifier stage can be added.
This circuit was found in an old American documentation on telecommunications. It is suitable for...
This circuit for discharging NiCad batteries limits the current to a value that can be adjusted in the...
This circuit was found in a 1997 publication, but it uses few common components and is very...