Technical Info - Crystals
The equivalent circuit is a circuit for an electrical activity of a quartz crystal unit operating at its natural resonant frequency. The C0, or shunt capacitance, represents the capacitance of the crystal electrodes plus the capacitance of the holder and leads. R1, C1 and L1 compose the "motional arm" of the crystal, and are referred to as the motional parameters. The motional inductance, L1 represents the vibrating the vibrating mass of the crystal unit. The motional capacitance, C1 represents the elasticity of the quartz and the resistance, R1 represents bulk losses occurring within the quartz.
As a crystal unit has a resistive element, this term is require in order to define and quantity that characteristic.
A process used in the manufacture of some types of crystal unit. The "etch" process results in an improved surface condition and an increase in the frequency if a blank. The word "etch" is also used to describe the material used in the "etch" process, as well as the process itself.