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Check Circuit

IP.com Disclosure Number: IPCOM000095579D
Original Publication Date: 1964-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Boogaard, C: AUTHOR

Abstract

The input voltage of the circuit can have a number of discrete values O, U, 2U, 3U, etc. The purpose of the circuit is to check whether the input voltage equals the value U. In this case a current must flow through a utilization device, e.g., lamp L. In all the other cases this current must be cut off.

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Check Circuit

The input voltage of the circuit can have a number of discrete values O, U, 2U, 3U, etc. The purpose of the circuit is to check whether the input voltage equals the value U. In this case a current must flow through a utilization device, e.g., lamp L. In all the other cases this current must be cut off.

Resistors R1, R2, R3 and R4 are chosen so that both transistors T1 and T2 are conducting when the input voltage has the normal value U. Current now flows through the lamp.

If the input voltage is zero, the bias of the base of T(1) and the emitter of T(2) are lowered. T(1) is cut off and no current flows. If the input voltage is 2U or more, the bias of the base of T(1) and the emitter of T(2) are raised. This turns off T(2). Again no current flows through the lamp.

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