COMPACT ELECTRIC APPARATUS POWERED BY SOLAR CELLS, IN PARTICULAR A SOLAR WATCH

摘要

A small electric device powered by solar cells and by a capacitive charge storage element has stable actuation assured during startup with an as yet uncharged capacitor. Startup problems are avoided by control of the power supply with a threshold value circuit that allows power to be supplied to device components when the components' minimum actuating voltage level has been attained at the capacitor. A deactuating voltage value of the threshold value circuit that is lower than the actuating voltage level prevents interruptions of operation similar to relaxation oscillation behavior due to temporarily increased actuating power requirements by causing deactivation of the components only if the capacitor voltage has dropped below a predetermined operational minimum. In this manner additional functions (such as radio watches with automatic hands setting devices or directional antennas, or ornamental pendulums or alarm or striking watches) which have components with higher acutating power requirements may be supplied without batteries by solar cells without having to overdimension the storage capacitor for the high startup load and thereby unnecessarily delay actuation of the device upon the exposure to radiation of the solar cells.