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Description: | Until the 1950s, accurate time measurement was based on the apparent movement of the stars and planets. Today we put crystals and atoms at the heart of our precision timekeepers. When an electric current is passed through a quartz crystal, it vibrates at a very precise frequency and creates a regular pulse for a clock mechanism. Quartz oscillators were first developed in the 1920s by radio engineers searching for accurate frequency sources. By the 1940s, quartz clocks had replaced pendulum regulators in the world's observatories.
This early General Post Office clock was used after 1945 for time signal transmissions from Rugby Radio Station and in the 1960s and 1970s was used in technical colleges as a teaching device. In 2006 it was restored to full working order by electrical and horology specialist, George Hammond, as a gift to the Observatory for the benefit of future researchers and visitors.
AQN: Hackney Technical College (owner). Mild-steel frame, constructed with bolts and rivets, containing circuits for the quartz crystal, temperature controlled heating element and dials for hours, minutes and seconds. Circuits are controlled by approx.30 valves of which at least three are lacking. With folder containing circuit diagrams, and instructions for setting-up and adjustment. Said to have been an experimental quartz clock in use at the GPO Experimental Station at Dollis Hill. Subsequently presented by the GPO to Hackney Technical College.
caption: Quartz masterclock 1944 - front view
caption: Quartz masterclock 1944 - 3/4 view
caption: Quartz masterclock 1944 - detail of valves
caption: Quartz masterclock 1944 - detail of quartz crystal chamber | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Subjects: | quartz crystal clocks master clocks GPO | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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