ULTRASTABLE CALIBRATED LIGHT SOURCE

摘要

Light from an electrically powered light source is optically monitored by a transducer which converts the optical signal to an electrical error signal. The error signal is compared with a reference signal and a signal representing the difference between the reference and the error signals is generated. The difference signal is employed to control an electronic switching network which in turn regulates the electrical power input to the light source to maintain a constant light level at the optical monitor.