It is quite simple to build a crystal oscillator by using a field impact transistor.
This low voltage crystal oscillator circuit functions at comparatively low supply voltages, from 1.5 volts upwards, and was screened with common-or-garden quartz crystals with frequencies which range from 100 kHz to 10 MHz.
The crystal is hooked up between drain and gate of the field impact transistor, T1, and operates in the similar resonance mode. Coil L1 is included to enhance the frequency range.
In addition, it helps as an extra similar coil for those crystals which are not specially fitted to this particular application and that do not effectively seem like oscillating.
Capacitor C1 is the series 'padding' capacitor for the crystal.
The essential feedback and the 180° phase shift is supplied by the internal input and output capacitance of the FET.
The output signal is buffered by transistor T2.
This low voltage crystal oscillator circuit was examined using the subsequent selection of crystals: 100 kHz, 1 MHz, 4 MHz, 6 MHz, 8 MHz and 10 MHz.
The circuit can be utilized in many different applications because of its low supply voltage specifications (1.5 V minimum)