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Switching Circuit

IP.com Disclosure Number: IPCOM000089941D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Abramson, P: AUTHOR [+3]

Abstract

In this transistor switching circuit, the closing of each one of sixty-four separate switch contacts provides output signals on a unique combination of three of twelve possible output leads. The switch consists of twenty-four NPN transistors. Four transistors C have their bases connected to positive voltage source V. Four transistors A transistors have their emitters connected to ground potential.

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Switching Circuit

In this transistor switching circuit, the closing of each one of sixty-four separate switch contacts provides output signals on a unique combination of three of twelve possible output leads. The switch consists of twenty-four NPN transistors. Four transistors C have their bases connected to positive voltage source V. Four transistors A transistors have their emitters connected to ground potential.

The emitter of any transistor C can be connected to the base of any transistor A via the base-emitter junction of one of sixteen switching transistors S and arranged in matrix form. The bases of transistors S can be selectively connected to the emitters of transistors C by switch contacts. The emitters of transistors S are connected to the bases of transistors A.

There are four open switch contacts at the base of each transistor S. When a switch contact is closed, a circuit path is formed from the plus potential to the base-emitter junction of a transistor C to the base-emitter junction of a transistor S and to the base-emitter junction of transistor A to ground. The potential on the collectors of the three transistors goes positive thus providing the unique three output signals on three of possible twelve leads labeled A1...A4, B1...B4 and C1...C4.

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