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Reset Circuit

IP.com Disclosure Number: IPCOM000093542D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Mello, AA: AUTHOR

Abstract

The arrangement is an electronic bipolar switch. When the signal at input terminal IN is at or near ground potential, diode D1 is forward biased by current flow through resistor R1. The voltage drop of the diode holds transistor T1 off and the collector of T1 is clamped to a potential of approximately +6 volts via circuit action of resistor R2 and diode D3. Transistor T2 is biased to its off condition so that the collector of T2 is negative and forward biases diode D4 and thus turns on transistor T3. The latter has its collector-emitter circuit connected across the terminals 01 and 02 to provide a path from these terminals for energy of a first polarity existing between 01 and 02.

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Reset Circuit

The arrangement is an electronic bipolar switch. When the signal at input terminal IN is at or near ground potential, diode D1 is forward biased by current flow through resistor R1. The voltage drop of the diode holds transistor T1 off and the collector of T1 is clamped to a potential of approximately +6 volts via circuit action of resistor R2 and diode D3. Transistor T2 is biased to its off condition so that the collector of T2 is negative and forward biases diode D4 and thus turns on transistor T3. The latter has its collector-emitter circuit connected across the terminals 01 and 02 to provide a path from these terminals for energy of a first polarity existing between 01 and 02.

At the same time the input signal forward biases diode D1, diode D5 is forward biased and current flows through resistor R4 turning on transistor T4. The collector of T4 goes positive and forward biases diode D6 which turns on transistor T5. The latter is connected in parallel with T3 across the terminals 01 and 02 and, being an NPN device, provides a discharge path for energy of opposite polarity at the terminals 01 ana 02.

When the input signal goes to 12 volts, D1 is reversed biased and current flow from R1 through diode D2 turns on T1. T2 turns on as the collector of T1 goes in a negative direction. With T2 on, the collector of T2 goes positive and reverse biases D4 as well as the base of T3. The latter is then turned off. The 12 volt input signal also reverse biases D...