Energy-saving supply circuit for fluorescent tube - has phototransistor controlling pulse width of supply oscillator depending on daylight intensity

摘要

The supply circuit has an oscillator generating a pulsed voltage of frequency most suitable for the fluorescent tube. A phototransistor or similar control element receives light from the tube and controls the pulse width of the oscillator. The phototransistor therefore adjusts the light intensity emitted by the tube taking daylight levels into account so that energy is saved.