A timepiece includes in addition to the conventional timekeeping circuits, high load, that is, high current circuits such as an alarm driving circuit and a lamp driving circuit. Low load, small current systems such as the oscillator, divider, display drivers and display for timekeeping are operated directly from the battery voltage source when the high load circuits are off. When the high load circuits are on, the low load circuits are disconnected from the battery and operate from an electric charge stored in a capacitor connected in parallel with the low load circuits. The high load circuits are driven intermittently at a high frequency to reduce power consumption and to permit recharging of the storage capacitor during off-periods. The drive frequency is sufficiently high such that an illumination lamp shows no flicker and brightness is controlled by duty cycle.