technical terms are generally use for crystal units:
wafer (blank) : A piece of quartz crystal cut as specified
in terms of shape, dimensions and orientation.
Electrode : Conductive
thin film vacuum-evaporated onto a crystal wafer to allow AC voltage to be applied.
Holder : A case
housing a crystal wafer, electrode and support to prevent them mechanically and
environmentally from being influenced by outside conditions, and also having terminals
permitting the electrical connection of the electrode with an outside circuit.
Crystal unit : Mounted crystal
wafer with electrode housed in a holder. Fundmental
The lowest frequency at which a specific crystal will vibrate.
Overtone : Odd numbers assigned
for frequencies in terms of specified oscillation mode (The first overtone is
called fundamental mode, followed by 3rd, 5th and 7th overtones, The frequencies
are not exactly three times, five times or seven times the fundamental mode.)
Series resonance frequency
: Lower frequency of the two given when the electrical impedance of a crystal
unit becomes resistant near resonance point.
capacitance : Effective series capacitance measured
from the terminals of a crystal unit to oscillation circuit and determined as
a condition in the case of using a crystal unit in an oscillation circuit. Operating
frequency is determined by the electrical characteristics of a crystal unit and
the load capacitance.
: Nominal value expressed in terms of frequency.
Series resonance : Condition
of resonance in the case of limitless load capacitance.
tolerance : Deviation from the nominal frequency expressed
by ratio in reference to nominal frequency.
series resistance : Equivalent resistance for series
Load Resonance Resistance
: Resistance for the lower (frequency of the two given when
the electrical impedance) becomes resistant near the resonance point of a circuit,
with the load capacitance connected with a crystal unit in series.
Operating temperature range :
Temperature range within which crystal units operate under specified conditions.
Drive level : Electric-power
or current level under the specified conditions of a crystal unit.
Main mode and spurious :
Main mode indicates the most prominent resonance frequency and spurious indicate
other resonance frequencies when there are some resonance frequencies near the