This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This circuit is quite simple to assemble, having been found in a traditional American publication. The...
This rectangular oscillator produces signals of two frequencies, one double the other. The circuit is...
This oscillator can generate signals up to about 10 MHz, depending on the crystal used. The...