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Three Voltage Band Detector

IP.com Disclosure Number: IPCOM000095790D
Original Publication Date: 1964-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

VonFeldt, JL: AUTHOR

Abstract

This voltage test probe functions to indicate deviation of signals from prescribed voltage limits of either polarity and from a specified band between said limits.

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Three Voltage Band Detector

This voltage test probe functions to indicate deviation of signals from prescribed voltage limits of either polarity and from a specified band between said limits.

When a signal less positive than +12 volts is applied to input terminal 1, emitter follower T2 applies this voltage to the emitter of inverter T3 to cause the latter to extinguish lamp 4. When the signal applied to terminal 1 is less negative than -3 volts, it turns off inverter T5 to extinguish lamp 6.

When the signal applied to terminal 1 lies between +. 01 volts and -. 4 volts, T2 applies this voltage to the commoned emitters of common base amplifiers T7 and T8 to turn both transistors on. When T7 and T8 conduct, they turn on the common emitter amplifiers T9 and T10 to energize lamp 11. However, if the input signal is more positive the +. 01 volts, the base-emitter junction of T7 reversely biases to turn T7 and T9 off to extinguish lamp 11. If the input signal is more negative than . 4 volts the base-emitter junction of T8 is reversely biased to turn off T8 and T10, extinguishing lamp 11.

Thus, lamp 11 is energized when the input voltage lies within the specified band for which the test probe is adjusted. The limits of this band are adjusted by means of the potentiometers 12 and 13.

An open circuit input condition extinguishes all lamps by reason of the low positive base bias on T2.

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