Mechanical wind-up antique clocks require manual power to operate.  A weight attached to a cord or a spring provides the force required to adjust the hands of the timepiece.  This force is first set into motion by the swinging of a pendulum, as a grandfather clock, or a teethed wheel in smaller clocks.  In the application of either a pendulum or a wheel, the force oscillates back and forth to the engineered intervals.  Clocks are designed with minimal friction for the oscillation pieces, yet both pendulums and wheels will eventually slow down and require adjusting.

Electric clocks, powered by battery or outlet, do not have a complex system of tension and torque.  Instead, a simple electric burst fires for power.  There are four different types of electric clocks. The one is a type that uses electricity to power the oscillation. One uses electricity to directly move the hands on the clock face, one uses electromagnetism to drive a pendulum, and one drives the faces of the clock with an internal motor, often relying upon the specific frequency of the clock’s own power source for accuracy.  In each of these electric clocks, the clock parts themselves do not change; only the mechanism for propelling the pendulum and hands varies.

Although craftsmen in Massachusetts began building clocks in the eighteenth century, most of their creations were clones of European designs until 1802, when one of these craftsmen patented the American banjo clock. This was the first truly American clock that launched a trend in American clock innovation that continues to this day. Nineteenth century American Banjo clocks have significant value as collector’s items today, but inexpensive replicas are also available.

At the time of its introduction, the American Banjo clock was known as the Improved Timepiece, with the banjo references being added later because of the similarity between the clock and the musical instrument. The basic design is geometrical in nature. A circle at the top of the clock features the clock face, below which there is a trapezoid which serves as the clock’s throat. At the bottom of the throat is a lower box that is rectangular. Most American Banjo clocks lacked any form of striking or chiming mechanism, so only indicated the time by its face, which was unusual for the period.

Most original American Banjo clocks were made primarily of mahogany wood that was imported to New England from the West Indies and used local pine and chestnut for the secondary woods. The clock mechanism itself was mostly made of metal, steel and brass in particular. Most of the exterior surface of the clock was surrounded by glass.

One of the key features of the American Banjo wall clock was the use of ornamental glass plates, which gave the clock a distinctive appearance. These glass plates and tablets had more in common with the produce of engravers than painters and involved several different styles of geometric design including detailed line work and semicircles. These engraved designs were done on a gold leaf base and were designed to work with gently colored backgrounds that gave the finished piece a subtle and unique beauty not seen previously in clock manufacture.

Authentic hand craft American Banjo clocks are still made today and there is a robust market of older antique banjo clocks as well. The price range differs widely depending on when the clock was made, its current condition, and who manufactured it. New American Banjo wall clocks can be found for around $200, while older antique ones can cost many thousands of dollars.

The famous Galileo, best known for determining that the Earth rotated around the Sun and not the other way around, was the first to invent the pendulum and began constructing one, but died before it was completed. A few years later, the Dutch natural philosopher Christian Huygens invented the first effective pendulum clock, based on Galileo’s earlier work, and patented it in 1657. This invention made clocks vastly more effective, cutting down the amount of inaccuracy from some fifteen minutes a day using a spring-driven clock down to some fifteen seconds a day using pendulum-driven ones.

The problem with pendulum clocks is that they require a lot of space so that the pendulum can swing freely. This was especially true of the original pendulum clocks in the seventeenth century whose swing was enormous, covering a one hundred degree angle. By about 1670 it had been discovered that these enormous swings in fact reduced the efficiency of the clocks so new mechanisms were invented allowing the same process to work, just with smaller pendulums swings at much smaller angles. This was more or less the beginning of the original pendulum clocks that are still used today and why these clocks were hung on the wall.

The popularity of pendulum driven clocks took off quickly. The improved accuracy allowed for the wide addition of minute hands to the clocks, which were largely meaningless using the older spring-driven clocks. Further, by 1680, the second hand was added, but in order to be accurate it required a pendulum of about a meter in length (about one yard), but since the swing was very small, this long pendulum could be encased, leading to the rise of standing grandfather clocks. By the beginning of the seventeenth century all of these new developments had taken place and having both wall clocks and free standing grandfather clocks became fashionable among the wealthy and those with a scientific inclination. Less than forty years after its invention, the pendulum clock had spawned a full blown, and successful, industry that continues to this day.

By the 1930s, when battery-driven electric clocks became the norm (although they were invented almost a century before), the pendulum clock remained the standard for home clocks of all types. Although legitimate pendulum clocks are still readily available, many inexpensive clocks today with pendulums are actually battery-driven electric ones with the pendulum added for aesthetic purposes only.