The Design of Stabilized Power Supplies for Incandescent Light Sources

Incandescent lamps are used as wide-band sources of light in many optical/electronic instruments, and the present paper describes some approaches to the design of stabilized power units for these lamps. Both dc and pulse-width modulated ac supplies are described, and a series of design equations for the latter are established. Where the lamp voltage is to be monitored rather than the light output itself, some unique advantages are claimed for the use of a lamp-photoresistor assembly (or calistor) within the feedback loop. Several example designs are given, from which a variety of power supplies may be developed.