Abstract

An indicating system for a radio receiver is formed of an indicator and associated control circuitry. The indicator is comprised of two emitting diodes wired in parallel and in reverse polarity, and encapsulated in a translucent package. Each diode in an indicator emits light of a visibly distinct wavelength when energized. The control circuitry causes a change in polarity of bias voltage applied to the indicator, and, in so doing a change in color of the indicator. With appropriate control circuitry, the color of the indicator indicates whether the receiver is tuned to an AM or FM station, or whether the station is broadcasting in mono or stereo. The indicator can be mounted to the dial pointer causing a change in pointer color with a change in receiver function. Additionally, the amount of current through the light emitting diodes and thus the intensity of emitted light may be varied in accordance with a parameter variation as, for example, accuracy of receiver tuning.