This circuit for a frequency of 10 kHz was found in an Electronic Design. It makes use of a tunnel diode. The transistor admits equivalent.
This circuit was found in a Popular Electronics from the 80s. It is possible to control a relay...
This simple low power triplicator was found in 90’s American documentation. The diodes can be...
The audio amplifier integrated circuit used in this 1990 project is not very common today....