Ever since the invention of clocks, clock makers have presented to us a large variety of different types of clocks. These clock types are especially designed for meeting varied needs. The basic function is simple—to tell time—however, the difference is in the construction and other functions and features. If you want to classify clocks, the main types will be mechanical, electric, pendulum, quartz and atomic clock.
A mechanical clock is made from simple mechanical components (not electrical). It is usually powered by a coiled spring or falling weights. The clock types that we usually know as grandfather, grandmother and cuckoo clock fall under this category. How accurately this clock can keep time depends on its construction and engineering of its components.
As the name suggests, an electric clock works on electricity that is supplied through a battery or other power source. The three main subtypes of electric clocks are impulsed clocks, electronic clocks, and rewound clocks. An impulsed clock has a mechanical system of time dividing, like a balance wheel and pendulum. However, it is powered by an electric source. On the other hand, a rewound clock has both a mechanical time dividing system and mechanical power supply system. The power supply system (like falling weights or a spring) is rewound by electricity. Lastly, the electronic clock has both electrical power supply and an electrical system for time dividing.
This type of clock uses a pendulum for time dividing. The good thing is that it improves the clock’s accuracy because its swinging has a special property. It is only the length of pendulum that determines the time for the pendulum to swing back and forth. Pendulum’s weight or the arc do not have an effect on the swinging.This makes a mechanical balance that allows consistent time dividing.
Quartz is type of an electric clock that has a quartz crystal. This crystal vibrates when electricity passes through it. The vibration is very consistent, which makes it a reliable mechanism for keeping time. The quartz crystal’s oscillation is known as a piezoelectric effect, and the electric circuits and quartz crystal are referred to as a quartz oscillator.
Atomic clocks are calibrated against the frequency of a resonating atom, usually cesium. These types of clocks are highly accurate. The NIST-FI atomic clock at the National Institute of Standards and Technology in Boulder, Colorado, is accurate to less than a second in more than 60 million years. Atomic clocks are expensive scientific tools used mostly in laboratories.