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The electric clock market grew rapidly in the 1930s, and Telechron's patented power interruption indicator gave his clocks an advantage over competing synchronous clocks, but by the 1950s battery-operated clocks that weren't dependent on the power grid took market share, and in the 1960s the quartz clock replaced synchronous clocks. The problem ...
Standby power may be used to power a display, operate a clock, etc., without switching the equipment to full power. Battery-powered equipment connected to mains electricity can be kept fully charged although switched on; for example, a mobile telephone can be ready to receive calls without depleting its battery charge.
These keep time by counting the oscillations of a calibrated tuning fork with a specific frequency. These were only made in battery-powered form. Battery-powered clocks have been made using the schemes above with the obvious exception of a synchronous movement. All battery-powered clocks have been largely replaced by the lower cost quartz movement.
In clocks that use AC power, a small backup battery is often included to keep the clock running if it is unplugged temporarily from the wall or during a power outage. Battery-powered analog wall clocks are available that operate over 15 years between battery changes.
Switching power dissipation is directly proportional to the switching activity (α), load capacitance (C), Supply voltage (V), and clock frequency (f) as: P = α·C·V 2 ·f. Switching activity means transition to different levels. Glitches are dependent on signal transitions and more glitches results in higher power dissipation.
In other instances, it can be used to reference the lack of basic user-friendly features in complex systems; stemming from the lack of a backup battery to keep the clock setting in a $300 VCR during even the briefest power interruption, when a $10 clock would have one. The term appears in the 1999 essay In the Beginning...
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Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency , so that quartz clocks and watches are at least an order of magnitude more accurate than mechanical clocks .
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