Robert A Mccurdy

US Patent:

52147827, May 25, 1993

Filed:

Dec 10, 1990

Appl. No.:

7/624584

Inventors:

Robert A. McCurdy - Spokane WA

Assignee:

Generic Computer Services - North Hollywood CA

International Classification:

G06F 1130
G06F 100

US Classification:

395750

Abstract:

An indicator circuit for indicating whether the supply voltages of a personal computer are or have been out of tolerance includes window comparators, control circuitry providing each window comparator with a sensed fraction of a particular power supply voltage, and a pair of light emitting diodes of significantly different colors connected in parallel but in opposite polarities. One of the light emitting diodes is normally energized to indicate a normal operating condition, and the other light emitting diode is normally not energized. A latch circuit is provided to switch power from the one LED to the other, to indicate an alarm condition. Output signals from all the window comparators are fed to an OR circuit which in turn controls the latch.