Browse Prior Art Database

PNPN Thyristor Flip Flop

IP.com Disclosure Number: IPCOM000096421D
Original Publication Date: 1963-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Razi, S: AUTHOR

Abstract

This circuit uses one PNPN transistor 9 to achieve a circuit having two stable states. In the off state, there is a small amount of current through transistor 9 and the voltage across 9 is large. In the on state, there is a large amount of current through transistor 9 and the voltage across it is small. A diode is connected in the emitter circuit of transistor 9 so that it can be changed from off to on with a minimum amount of input energy.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 75% of the total text.

Page 1 of 2

PNPN Thyristor Flip Flop

This circuit uses one PNPN transistor 9 to achieve a circuit having two stable states. In the off state, there is a small amount of current through transistor 9 and the voltage across 9 is large. In the on state, there is a large amount of current through transistor 9 and the voltage across it is small. A diode is connected in the emitter circuit of transistor 9 so that it can be changed from off to on with a minimum amount of input energy.

The circuit has one input. As pulses are repeatedly applied to this input, the circuit alternately changes from off to on and then from on to off. Assuming that the transistor is initially off, as the pulses are applied to the input, the circuit operates as follows.

As the input goes from a minus voltage to 0, diode 11 becomes forwardly biased and the pulse is transmitted to the emitter of transistor 9 via capacitor 13. The voltage which is developed across the high impedance of reversely biased diode 15 is sufficient to turn transistor 9 on.

Diode 17 remains reversely biased preventing the input pulse from appearing at the base of transistor 9. The falling edge b of the first input pulse has no effect on the circuit operation. Just prior to the appearance of the second input pulse, points 19 and 21 are at ground potential and diode 11 is reversely biased. The positive jump of the input at c is transmitted through capacitor 23 and diode 17 to the base of transistor 9 causing it to turn off. Thus, trans...