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Light Emitting Diode Circuit

IP.com Disclosure Number: IPCOM000076851D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Lyons, VJ: AUTHOR [+2]

Abstract

This light-emitting diode circuit incorporates a plurality of diodes, each capable of emitting different wavelength light within the visible spectrum. Diode 2 having a lower threshold level and capable of emitting a longer wavelength light, e.g. red, and diode 3 having a higher threshold level and capable of emitting a shorter wavelength light, e.g. green, are connected in parallel to an adjustable power supply 1. A series resistor 4 is connected to diode 2 to prevent excessive current flowing through diode 2.

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Light Emitting Diode Circuit

This light-emitting diode circuit incorporates a plurality of diodes, each capable of emitting different wavelength light within the visible spectrum. Diode 2 having a lower threshold level and capable of emitting a longer wavelength light, e.g. red, and diode 3 having a higher threshold level and capable of emitting a shorter wavelength light, e.g. green, are connected in parallel to an adjustable power supply 1. A series resistor 4 is connected to diode 2 to prevent excessive current flowing through diode 2.

When the voltage applied to this circuit is lower than threshold level of diode 3 but higher than that of diode 2, only diode 2 emits a red light. Upon increasing the voltage, diode 3 glows and increases in intensity with increasing voltage, while the intensity of the red light is limited by resistor 4. Thus a state is reached where diodes 2 and 3 are emitting simultaneously.

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