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Transistor Flip-Flop

IP.com Disclosure Number: IPCOM000097971D
Original Publication Date: 1961-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Earle, J: AUTHOR

Abstract

The two-collector transistor, Rutz, IBM Journal of Research and Development, July 1957, Vol. 1, No. 3, page 212, and its associated circuitry, operates as a D.C. flip-flop. The value of the resistor 30 is chosen so that it allows passage of a certain number of units of current. Set and Reset terminals S and R are the inputs. The outputs are from terminals 44 and 46.

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Transistor Flip-Flop

The two-collector transistor, Rutz, IBM Journal of Research and Development, July 1957, Vol. 1, No. 3, page 212, and its associated circuitry, operates as a D.C. flip-flop. The value of the resistor 30 is chosen so that it allows passage of a certain number of units of current. Set and Reset terminals S and R are the inputs. The outputs are from terminals 44 and 46.

Assume the value of resistor 30 permits three units of current to pass, and the resistors 34, 36 and 38 are each of a value which will drain one unit of current when their respective terminals are at logical zero -V volts. Further assume the circuit is in the first of its stable states. Then terminal 46 is at logical one 0 volts, terminal 44 at logical zero -V volts, input terminal 40 is at logical zero and terminal 42 at logical one.

Terminals S and 44 each drain one unit of current, leaving one unit from the source to enter the emitter. Thus, one unit of emitter current places the transistor in state 2 with collector 1 conducting and collector 2 not conducting (upper drawing).

Triggering pulses effect switching at the input terminals S and R. The flip-flop is switched by a pulse at S, going from -V volts to ground, or a pulse going from logical zero to logical one. Now two units of emitter current are present. These two units of current tend to start collector 2 conducting and shut off collector 1. But collector 2 begins conducting before collector 1 ceases. As soon as collector 2 starts conducting, the unit of current which resistor 38 previously d...