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.
When the sensor connected to points A and B is activated, removing the ground from the base of Q1...
This oscillator was found in the 1994 National Instruments Linear Applications Handbook. The...
With the circuit shown in the figure, the frequency of a 5 MHz oscillator controlled by crystal can...