Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a 12V relay. The circuit can be implemented with modern equivalent components.
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...
The presented circuit was suggested by the 1994 Linear Applications Handbook from National...
This circuit was found in a Motorola documentation from 1968. The load current is 10 A. The...