Pendulum clock is to use the periodic vibration (swing) process of the pendulum to measure time, time = the vibration period of the pendulum × the number of vibrations. And the oscillation period of the pendulum
T = 2π(l \/ g) ^ 0.5
Generally speaking, the weight of the pendulum is determined, and the vibration period of the pendulum can be adjusted by adjusting the quoted length (l) of the pendulum. The reference length of the pendulum is reduced, and the clock is faster; Otherwise, it slows down. For precision pendulum clocks, the additional weight method is also useful to fine tune the vibration period of the pendulum. When pendulum clocks are placed in different geographical locations (different latitudes and altitudes of the Earth), the acceleration of gravity of the pendulum will change and affect its vibration period. Pendulum clocks placed in different temperature and pressure environments will also cause changes in the vibration period. Temperature changes can cause changes in the dimensions of various parts of the pendulum, including the reference length of the pendulum. Generally, the temperature increases, the pendulum expands longer and the clock slows down; Otherwise, the pendulum shortens and the clock speeds up. Therefore, precision pendulum clocks are commonly used to make temperature compensation tubes with different linear expansion coefficients to compensate for temperature effects. The change of air pressure will cause the change of air resistance and air density, which will cause the change of vibration period. Therefore, precision pendulum clocks often install the pendulum in a constant pressure housing to eliminate the effect of air pressure.
The amplitude of the pendulum affects the isochronism of the clock. The smaller the amplitude, the smaller the change in the daily difference caused by the amplitude change (see clock day difference), that is, the better the isochronicity, so the precision pendulum clock often uses a long pendulum rod small swing. However, the small swing is very sensitive to external vibration and impact, so the installation environment is very demanding. The time difference of pendulum clocks can generally reach within 20 seconds\/day, and precision pendulum clocks can reach a few thousandths of a second.
The pendulum is swayed by the mutual conversion of gravitational potential energy and kinetic energy to swing, simply put, if you pull the pendulum up, it will swing down due to the influence of gravity, and when it reaches the lowest position, it has a speed, it can not stop directly (just like the brake can not stop all at once), it will continue to rush through the lowest position. The reason it swings back at its highest position is because gravity slows it down until it reaches 0, and then swings back (just like lifting something up into the sky, it slows down to 0 on the way up and then falls). And back and forth, it keeps swinging.
According to the above, the pendulum can swing forever, but because of the presence of resistance, it will gradually reduce the swing and finally stop. So you use a clockwork to provide the energy to make it swing.
Pendulum clocks are made by letting the gears run at a constant speed, a bunch of gears crisscrossed inside the clock, specially responsible for counting how many seconds have passed, and then converted into minutes and hours, and then displayed on the clock face for people to watch the time.
Pendulum clock work mainly uses the isochronism of the pendulum, and there is a clever application of the combination of gear and escapement, using the same time used by the pendulum each single pendulum to control the escapement cross retracting gear, so this is also the reason why we hear the pendulum clock ticking.