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Inverse Exclusive OR Circuit

IP.com Disclosure Number: IPCOM000093731D
Original Publication Date: 1966-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Jen, TS: AUTHOR

Abstract

This circuit provides the inverse of the Exclusive-Or function. Use is made of emitter-follower inputs to provide energizing levels to transistors connected in the current switch configuration.

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Inverse Exclusive OR Circuit

This circuit provides the inverse of the Exclusive-Or function. Use is made of emitter-follower inputs to provide energizing levels to transistors connected in the current switch configuration.

Logical inputs A and B are applied via conductors 2 and 4 to transistor T6 and T8 respectively. T6 and T8 are connected in emitter-follower configuration and use tapped emitter resistors to provide their outputs. Transistor pairs T10 and T12 and T14 and T16 are respectively connected in the current switch configuration. Their emitters are respectively coupled through resistors 18 and 20 to a source of negative potential -V. The Exclusive-Or output is taken at terminal 22 across resistor 24. The base inputs for T10 and T16 are derived via conductors 26 and 28 across emitter resistances 30 and 32 and 34 and 36. The base inputs to T12 and T14 are derived via conductors 38 and 40 from the tap between the respective emitter resistances.

If either one of the A or B inputs is at the up logical level, one of T6 or T8 is rendered more heavily conductive. The increased conduction of that transistor causes a corresponding potential rise across its emitter resistances. Such action causes like potential rises on its respectively connected pair of output conductors. Thus, if the A input is high and the B input is low, the potential on conductor 26 is more positive than the potential on conductor 38. Both conductors 26 and 38 are thus provided with more posit...