What Types of Clocks Are There?

eHow may earn compensation through affiliate links in this story. Learn more about our affiliate and product review process here.
Clocks come in many different types.

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.


Mechanical Clock

Video of the Day

Mechanical clocks' accuracy is dependent on their construction and components.

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.

Video of the Day

Electric Clock

Modern alarm clocks are often electric clocks.

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.


Pendulum Clock

Pendulum clocks make use of the pendulum's swaying motion to keep accurate time.

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 Clock

In quartz clocks, the quartz crystal allows for precise timekeeping.

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 Clock

Atomic clocks are the most accurate clocks in the world.

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.