This 80's General Electric circuit is guarded by the noise-guard for operating current. The circuit has an input sensitivity of 3 pA. The font must be symmetrical.
This National Semiconductor circuit appears elsewhere on this site. The circuit must be powered by...
In this circuit the frequency is determined by the coil and the variable capacitor. Transistors like the...
This circuit is from old American documentation, but the transistor used is still very common...