Electric clocks {clock} use synchronous motors, which turn at 60 cycles per second, USA AC-current frequency. Electric motor replaces pendulum, escapement, and spring or weight.
Clocks {atomic clock}| can use cesium-atom vibrations to establish frequency.
Clocks and watches can have oscillating wheels {balance wheel}| that determine frequency.
Clocks {cesium clock}| can depend on cesium emission-spectrum wavelength.
very accurate clock {chronometer}|.
Clock parts {escapement}| can transfer power from main spring to gears, by oscillating. Escapement has pendulum, ratchet, and gear.
spring
Springs {mainspring} are coiled or flat steel ribbon, which is wound to provide energy.
oscillation
Clocks with a hanging pendulum use gravity for back-and-forth oscillation. Weight hangs on chain, as in cuckoo clocks. Clocks with a circular pendulum use a hairspring and lever for oscillation.
Pendulum connects to ratchet, which engages gear teeth. Alternatively, ratchet can press against gears to escapement wheel, so wheel turns one notch if released by ratchet. The mechanism pushes ratchet lightly, which pushes pendulum slightly and keeps pendulum moving in spite of friction.
process
Oscillation in one direction moves gear one step forward. Oscillation in other direction moves ratchet into position to receive next forward motion. Oscillation takes a fixed time, which shortening or lengthening can adjust.
Two spherical chambers can have narrow constriction between them through which fine sand flows {hourglass, clock}|.
Maser clocks {hydrogen clock}| depend on hydrogen emission wavelengths and are accurate to one part in 10^15.
Clocks {quartz clock}| can use quartz-crystal oscillations in escapement. A battery provides current that oscillates crystal.
Clocks {timer}| can mechanically or electrically start or start movements, at specific times.
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225