This circuit is from a 1974 publication by Motorola. The unijunction may be 2N2646 and bipolar BC558 and BC548. The pulse duration depends on the capacitor.
This circuit uses only passive components and the instrument can be a microammeter or the lowest...
This circuit is from a 1967 RCA documentation. Components can be replaced with modern equivalents. The...
This circuit for the car was found in the April 1990 Radio Electronics magazine. The speaker is...