Browse Prior Art Database

Precision Amplifier

IP.com Disclosure Number: IPCOM000094502D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Bojman, W: AUTHOR [+2]

Abstract

This is a voltage holding operational amplifier with a high input impedance.

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Precision Amplifier

This is a voltage holding operational amplifier with a high input impedance.

Operational amplifier 10 is provided with differential input terminals 12 and 14 across which an input potential E is applied. Power supplies 16 and 18 are connected to the ground through resistor R1 and provide the amplifier operating potentials. Resistor R2 and capacitor 20 are, respectively, the load impedance and voltage holding element for amplifier 10.

If the input potential rises, the output of amplifier 10 shifts in a negative direction causing a current to be drawn from ground through R2, into the amplifier's output, through supply 16 and into R1 to ground. The current through R1 opposes the input potential and is a form of degenerative feedback and, in effect, provides amplifier 10 with its increased input impedance. If, on the other hand, the input potential decreases, the current path reverses and causes current to pass through R1, supply 18, through amplifier 10 and R2 to ground. The potential developed across R1 still opposes the input potential and provides the desired increased input impedance. The overall gain of the amplifier 10 can be established at any desired level by the proper choice of R1 and R2.

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