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Temperature Sensing Device

IP.com Disclosure Number: IPCOM000081694D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Atkey, P: AUTHOR [+2]

Abstract

A thermistor is mounted in a disc and changes the flashing frequency of a light-emitting diode mounted at the apex of the disk spindle. The transmitter, shown in Fig. 1, consists of an oscillator 1 with an emitter-follower 2 at the input and a feedback loop including the thermistor 3, which determines the rate of oscillation. The oscillator 1 drives light-emitting diode (LED) 4.

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Temperature Sensing Device

A thermistor is mounted in a disc and changes the flashing frequency of a light-emitting diode mounted at the apex of the disk spindle. The transmitter, shown in Fig. 1, consists of an oscillator 1 with an emitter-follower 2 at the input and a feedback loop including the thermistor 3, which determines the rate of oscillation.

The oscillator 1 drives light-emitting diode (LED) 4.

The receiver is shown in Fig. 2. The light output of LED 4 is sensed by a photodiode 5 forming part of amplifier 6 connected to a voltage comparator 7, the output 8 of which is a square wave with a mark-to-space ratio determined essentially by the signal from the photodiode 5.

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