This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
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...