Browse Prior Art Database

Analog Storage Circuit

IP.com Disclosure Number: IPCOM000092619D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Beck, JW: AUTHOR

Abstract

In process control applications, utilization of field-effect transistor 10, a high input impedance device, as a DC amplifier provides certain advantages. With the cooperation of associated circuitry, FET 10 transduces the charge stored on capacitor 12 to a usable current across output terminals 14.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Analog Storage Circuit

In process control applications, utilization of field-effect transistor 10, a high input impedance device, as a DC amplifier provides certain advantages. With the cooperation of associated circuitry, FET 10 transduces the charge stored on capacitor 12 to a usable current across output terminals 14.

The current across terminals 14 varies in accordance with the charge stored on capacitor 12. In order to provide the necessary current variation across terminals 14, a relatively large positive voltage source 16 is connected to FET 10. By inserting circuitry comprising a first transistor 18, resistors 20 and 22, and zener diode 24 between voltage source 16 and the drain 26 of FET 10, the voltage available from source 16 is lowered to a value compatible with the characteristics of FET 10. Transistor 18 and diode 24 also serve to immunize FET 10 from variations in the voltage supplied by source 16, thus making it possible to use a relatively low-grade voltage source. A second transistor 28 and its associated resistor 30 allows the desired current changes to be developed across terminals 14 by serving as a current amplifier.

Relays 32 and 34 serve to connect FET 10 to a comparison circuit. When FET 10 operates as a DC amplifier to transfer the charge stored on capacitor 12, a portion of the output current is fed back through resistor 36 and closed contacts of relays 32 and 34. Resistor 36 is selected so that when the current generated by FET 10 equa...