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.
Lamp Control (CB25902E) This low-current control circuit has a lamp as a load, but can have other...
This circuit operates from 25 to 65 kHz depending on the transducer used and the settings. We...
This TTL module can be used in counter and many of them can be cascaded to counts up to 99, 999,...