This simple low power triplicator was found in 90’s American documentation. The diodes can be general purpose types and the frequency is determined by the RC network of the 555.
This circuit is from a Popular Electronics from the 90s. The circuit has a tone frequency...
This solar powered circuit was found in a 1991 documentation. The transistor is a general purpose...
This circuit is based on a common cathode 7-segment display. The circuit is based on CMOS...