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CMOS Sensitive Contact

IP.com Disclosure Number: IPCOM000051769D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Sellier, D: AUTHOR

Abstract

Shown above is a device for making a contact in a sensitive way by simply touching a key with the finger. Since it comprises no mechanical parts, its reliability and life are high.

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CMOS Sensitive Contact

Shown above is a device for making a contact in a sensitive way by simply touching a key with the finger. Since it comprises no mechanical parts, its reliability and life are high.

The sensitive key is used with a simple logic circuit for detecting the contact status without requiring any initial adjustment. This is done by detecting an electrical noise.

The input of a high input impedance amplifier comprising CMOS gate G1 is connected to sensitive metallic key K1. No signal is provided at the output of gate G1. When the key is touched, a periodical clamped signal is provided due to the amplified electrical noise which saturates CMOS gate G1.

The status change at the output of CMOS gate G1 is detected. This causes bistable latch L1 to be latched.

CMOS gate G2 and key K2 are used together with an OR circuit, retriggerable single-shot SS1 and single-shot SS2 to reset latch L1 to its initial state.

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