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Touch Sensitive Circuits

IP.com Disclosure Number: IPCOM000096707D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Nick, H: AUTHOR

Abstract

In the touch sensitive circuit, electrodes E1 and E2 are sufficiently closely spaced so that they can be simultaneously touched by an operator' s finger tip. An electrical connection is established through the skin of the finger tip raising the potential at E1. This change in potential is AC coupled through a previously charged capacitor C1 causing a neon N1 to conduct. The voltage across its electrodes drops sharply causing a positive pulse to appear at the output.

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Touch Sensitive Circuits

In the touch sensitive circuit, electrodes E1 and E2 are sufficiently closely spaced so that they can be simultaneously touched by an operator' s finger tip. An electrical connection is established through the skin of the finger tip raising the potential at E1. This change in potential is AC coupled through a previously charged capacitor C1 causing a neon N1 to conduct. The voltage across its electrodes drops sharply causing a positive pulse to appear at the output.

N1 is alternatively ignited by applying a negative potential to the DC set line so as to take D1 out of conduction. The resulting voltage drop at point A causes N1 to conduct. When N1 is ignited it remains in the conducting state until the AC reset line is energized.

The positive portion of the AC voltage is coupled through D2 and C2. The resulting voltage rise at point A causes N1 to shut off. The polarity of D3 inhibits the transmission of a pulse to the output during shutoff.

The lower drawing shows a touch set, touch reset latch circuit which has two neon tube circuits of the type shown above. Elements 1, 2, 3 and 4 form a first latch circuit. Elements 5, 6, 7 and 8 form a second latch circuit. Lines 9 and 10 cross couple the two latch circuits so that the setting of one causes the resetting of the other. The outputs of the two latch circuits are coupled back to the AC reset lines of their associated touch sensitive neon tube circuits. Such is through inverters 11 and 12 s...