Glossary - alphabet order - "H"

Hermetic seal

A hermetic seal is part of a metal can package that allows a lead (pin) to protrude from the package while maintaining the vacuum condition and insulation of the output signal.

Structure diagram of crystal unit


Hertz is a unit of frequency. See "Hz".

Reference: Hz , frequency

High frequency

The high frequency band is in the megahertz (MHz) section of the frequency spectrum.

Reference: Frequency band

High-stability crystal oscillator

This name is used to distinguish this type of crystal oscillator from ordinary clock oscillators. Among Seiko Epson products, this indicates that the oscillator's frequency stability has a precision range better than ± 30 × 10-6. High-precision oscillators generally include a crystal oscillator that has superior temperature and ageing characteristics as well as a crystal oscillation circuit that has superior power supply voltage variation and load variation characteristics.


This is the symbol for Hertz, a unit of measure for frequency. 103 Hz = 1 kHz (kilohertz), 106 Hz = 1 MHz (megahertz), and 109 Hz = 1 GHz (gigahertz).

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