Hello folks, I've been trying to understand how crystals work in crystal oscillator circuits. I understand the piezoelectric effect to the following extent: If we apply an electric field to the crystal it will deform and when the field is removed, the crystal will generate an electric field in the opposite direction. I get stuck at the point where the electric field is removed. I can't seem to understand how the electric field is removed in crystal oscillator circuits. I've attached a diagram of a crystal oscillator circuit. I'm looking for a qualitative analysis of the circuit without using the RLC model of a crystal. I'm trying to understand what exactly happens to the crystal during oscillation. What I'm looking for in terms of an analysis, is an explanation similar to the following one: base voltage of Q1 increases, which increases voltage at the emitter which increases current through R1, etc, etc, etc, around the loop. Thanks.