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Voltage Detection Circuit

IP.com Disclosure Number: IPCOM000098481D
Original Publication Date: 1960-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

O'Malley, FL: AUTHOR

Abstract

The circuit senses under and over voltages in D.C. power supplies. When either of these out of tolerance conditions exist, an error signal of go no go type is generated.

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Voltage Detection Circuit

The circuit senses under and over voltages in D.C. power supplies. When either of these out of tolerance conditions exist, an error signal of go no go type is generated.

Vs is the voltage being sensed. When Vs is at its proper potential, the voltage at A equals the voltage at B and the transistor Q1 is off. An over voltage causes the voltage at B to be more positive than that at A. Diodes CR2 and CR3 are enabled, thus turning Q1 on. An under voltage causes the voltage at B to be more negative than that at A. Diodes CR1 and CR4 are enabled, thus turning Q1 on. The transistor, when on, drives point C positive and forces the diode CR5 into avalanche break down. This lights the lamp L and provides the error signal Eo.

The sensitivity of the circuit is improved by replacing R1 with a Zener diode or using a Zener diode for CR6 very nearly equal in voltage to Vs, and by decreasing the value of R2.

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