SIX QUARTZ CRYSTAL UNITS MADE BY STC TO THE, 1960's

Various types of Quartz crystal units dating from the 1940's. Quartz crystals are used in many electronic systems for providing stable oscillators, such as Signal Generators, Communication Transceivers, they are used for filters as well, possibly a more common use in modern equipment. Also any equipment that needs to remain stable in operation. Such is the importance of stability in some applications that these units are operated inside temperature controlled ovens. One disadvantage of quartz is that it continues to change over time, over many years the value to which these units are made will vary slightly, causing an error requiring a replacement of the unit. Variation is usually 1 in 1000,000,000 times per day.
For Synthetic Quartz See Item A1421.

Nortel Collection

A1424