Tri-Color LED Drive System
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
A technique is described whereby a tri-color light-emitting diode (LED) is interfaced with a microprocessor controlled drive circuit so as to provide a low cost status indicator. The intent is to replace expensive displays, such as analog meters, incandescent lamps and analog or digital status monitoring devices. Commercially available tri-color LEDs have red and green light emitting diodes encased in a single holder with two operational leads. The LED emits a red light when a continuous voltage of one polarity is applied to the leads, a green light when the voltage polarity is reversed, and when the voltage polarity is switched rapidly, the eye averages the red and green colors so that the LED appears as yellow or orange.