The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The current in the drain is about 500 uA. Crystals from other frequencies can be used.
In the figure we have a simple timer with the 555 feeding a relay directly. The circuit is from...
This is the power step of the previous circuit. Output transistors must be mounted on good heat...
We found this circuit in a publication of 1991. The audio amplifier is an operational that admits...