Found in General Electric's 1969 documentation, this circuit uses two Foto Darlingtons to control the SCRs driving phases. SCRs can be equivalent current types.
This circuit only generates the voltage that must be pulsed in an EPROM to make its recording. The pulsar...
This source was found in a 1982 American publication, but can be easily assembled using 2N2995 (PNP...
This 1990 circuit uses LEDs on a display with individual LEDs that form the hours and minutes. The circuit...