National Transistor Clock Japan Battery Pendulum

Draft- Awaiting more information??

Description

A battery-powered, electro-mechanical pendulum clock from National Japan, the National Transistor Clock. c1970. So cute. So rare too! Only one on eBay worldwide and in Australia too.

Significance

A Japanese battery pendulum clock in a glass case c1970, similar to the earlier Bulle clocks, 1920 to 1950s. Similarly, the battery-powered pendulm movement avoids the need to wind a spring. At a guess, the battery lasts about a year.

Made in the period just after transistors became avaiable but just before quartz electronic clocks dominated, so numbers are low.

Transistor switching is used for power to the electromagnetic coils that the pendulum swings between. The pendulum is a permanent magnet(??). In the Bulle clocks, the permanent magnet is fixed and the electromagnet is on the pendulum, with mechanical switching. Transistor switching is mechanically simpler but the pendulum has the weight of a iron permanent magnet.

Howard Millar made a similar transistor clock c1970 but with a single fixed coil in the middle. Ditto Toshiba but in a plastic enclosure.

National Transistor Clock. In removable glass case. Pendulum swings between electromagnets.

Side view showing gear mechanism to drive the hands, but no electrical switching, unlike Bulle clocks.

Rear view shows construction.

Battery and cover for electronics. To be unassembled??

Howard Millar clock uses a similar arrangement but one fixed electro magnet. Not my clock (yet!).

Underside showing some electronics and battery. 



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