Digital clocks use numbers to show the time. LCDs and LEDs are common for digital clocks. Unlike analog clocks which are based on 12 hours, digital clocks can use either a 12-hour clock (often with "am" for morning and "pm" for afternoon/night) or a 24-hour clock. Digital clocks are usually smaller and easier to both use and read than analog clocks but they can also be made much larger. New digital clocks can even correct themselves using the internet or radio signals.