There are three distinct types of quartz watches, but each is powered by an automatically moving battery. An analog quartz is the same as a mechanical watch in that it has gears to transmit power, but it is battery-powered and oscillates using a quartz crystal to maintain precision. A digital quartz watch uses an electronic circuit instead of gears for movement. And a solar quartz watch uses battery power from various light sources, which is charged in the solar cell underneath the dial. These can be analog or digital, and are defined by being either battery- or solar-powered.