Found in a 1965 Electronic Design, this circuit divides the frequency of a cascaded signal using unijunction transistors. The bipolar transistor supports an equivalent. The shock is 470 mH.
This setting appears multiple times on the site from different sources. This is from a 2000 manual...
This amplifier was found in a 1970s documentation. Darlington transistors can be replaced for modern...
This circuit is from a Modern Electronics from April 1990. The circuit can be assembled with BC558...