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.
In this amplifier, the supply voltage is 35 V and the input resistance is 2k2. Equivalent...
This high speed laser diode driver was found in a 1980s documentation. Power FETs can be replaced...
This instrumentation amplifier with differential inputs was found in documentation from the 90s....