Found in Ferranti's 1969 documentation, this circuit can be mounted with a modern equivalent transistor. The circuit has a 4 V immunity and can be used as a shield for sensors.
This circuit determines the frequency of a signal by beating with a known signal. The circuit was...
With the values of the components indicated, this timer controls intervals from a few seconds to a...
The purpose of this circuit is to automatically turn a water pump on and off. Sensor 1 is the...