WATCHES
Mechanical watches
Mechanical watches need energy to work. They can be wound by two technologies. The difference is, how the mainspring is wound:
- Manual – by turning the winding crown
- Automatic – by turning a rotor inside the watch (by the motion of wearer’s arm)
Potential energy is stored in the coiled spring, then released to the gear train (series of small gears) which transmits the power to the escapement, which restricts the mechanical impulses of the gear train into equal, regular parts, turning the balance wheel (the time regulating organ, which vibrates on a spiral hairspring). The hairspring can be lengthened or shortened to adjust the timekeeping. A series of gears, called the motion work, then turns the hands on the watch face.
Advantages
- Doesn’t need to change battery
- Service life almost forever
- Typical mechanical watch uses purely mechanical components (can be repaired)
- It’s traditional
Disadvantages
- Manual – need to be wound
- Automatic – if we won’t wear them, they’ll stop working
- Need regularly cleaning, lubrication, balancing
- Less accurate timekeeping – has some variation every day
How mechanical watches work
Quartz crystal watches
A miniature battery supplies the power to an integrated circuit (chip), which in turn causes a quartz crystal to vibrate at a constant 32.768 times per second. These vibrations are then divided by the chip 16 times until only 1 vibration per second. The chip passes this to the stepping motor, which converts it to a mechanical impulse to drive the hands via the gear train.
Advantages
- Doesn’t stop working once removed from a wrist (powered by battery)
- Good for active people
- Provide highly accurate timekeeping – about one minute per year
- Advanced technology
Disadvantages
- Need change battery
- Mostly can’t be repaired, only replaced, because of electronics components
- Water resistant models need to be resealed each time a battery is changed
How quartz crystal watches work
Kinetic watches
Kinetic watches have a half moon shape weight inside that spins around in either direction every time the watch is moved in a similar way the automatic mechanical watch, a normal days wear will cause it to spin many thousands of times. This weight is connected at its centre to a rotor which turns within a coil block thus generating electricity. This electrical energy is fed to the integrated circuit (IC), which in turn causes a quartz crystal to vibrate at a constant 32.768 times per second. These vibrations are then divided by the chip 16 times until only 1 vibration per second. The chip passes this to the stepping motor, which converts it to a mechanical impulse to drive the hands via the gear train.
Advantages
- Never need winding or a battery change (by wearing continually generates and stores electricity)
- Provide accurate timekeeping
- Reliable
- Advanced technology
Disadvantages
- Main capacitor that stores the energy will eventually wear out and need to be replaced
How kinetic watches work
Eco-drive watches
Eco-drive watches receive their energy from light. A solar panel behind the watch dial 'traps' this energy and passes it to the capacitor. This electrical energy is now stored inside a capacitor which can be thought of as a rechargeable battery. This electrical energy is fed to the integrated circuit (IC), which in turn causes a quartz crystal to vibrate at a constant 32.768 times per second. These vibrations are then divided by the chip 16 times until only 1 vibration per second. The chip passes this to the stepping motor, which converts it to a mechanical impulse to drive the hands via the gear train.
Advantages
- Never need a battery replaced
- Environmentaly friendly
Disadvantages
- Need maintenance for movements in regular intervals
How eco-drive watches work
