This circuit was found in a 90s American publication. The same configuration appears in several places on this site, obtained from different sources. The lamps can be replaced by LEDs.
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...