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Browse Prior Art Database

Current Sensor

IP.com Disclosure Number: IPCOM000085398D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Bingham, DG: AUTHOR [+2]

Abstract

Telephone line DC current can be reliably detected by adding a current control to an optical coupler.

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Current Sensor

Telephone line DC current can be reliably detected by adding a current control to an optical coupler.

The component values are chosen such that over a possible range of positive I "in", I "load" is approximately constant. I load can then be limited to reasonable values independent of the magnitude of I in. DC resistance is determined primarily by diode R1, R2, and diode D1. R1 and R2 are chosen such that the nonlinear effect of the DC resistance of diode D1 is minimized. Also, resistor R2 is chosen such that I in is positive before I load is applied.

With this circuit, current which may vary greatly from one detection to the next can be sensed. Further, a relatively constant DC resistance is presented over the range of expected current variation.

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