Clock (Project)

Project Number: 21

Description: Build the circuit shown. Set the meter (M6) to the 0.5mA setting. The clock display will light, but the meter will not measure any current. See page 4 if you would like to set the time. The clock needs only about 0.005mA of current to operate, and this is too small to measure on your meter. The battery can run the clock for a long time without being recharged.

Snappy: The clock uses a liquid crystal display (LCD) to show the time. LCDs use very little power, but cannot be viewed in darkness. The electronic circuitry that keeps time, controls the display, and allows you to set the current time is complex but has been miniaturized in an integrated circuit (IC).