Browse Prior Art Database

Single Junction Type Transistor Trigger and Indicator

IP.com Disclosure Number: IPCOM000098209D
Original Publication Date: 1960-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Mazure, A: AUTHOR

Abstract

The drawing shows a trigger circuit utilizing a single junction type transistor and a neon bulb, the latter providing both a latching function and an indication of the state of the trigger.

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Single Junction Type Transistor Trigger and Indicator

The drawing shows a trigger circuit utilizing a single junction type transistor and a neon bulb, the latter providing both a latching function and an indication of the state of the trigger.

Assume that upon application of power, the transistor is conducting. In this condition, the outout A is approximately at ground potential. The resultant voltage across the neon bulb is then insufficient to cause it to light. Point B is also approximately at ground potential and the base of the transistor is maintained at a negative potential through the voltage divider action of R(2), R(3) and R(4), the latter being returned to a source of negative voltage.

The trigger is turned off by application of a positive voltage at the OFF input coincident with rising of the OFF gate terminal to ground potential. The positive pulse passes through diode D(1) to reversely bias the emitter-base junction of the transistor. As the transistor turns off, its collector voltage, and thus the voltage at terminal A, falls towards its collector level, -45 volts. At this time, there is sufficient voltage across the neon bulb to ignite it. Upon firing, the neon becomes a very low impedance and point C assumes a voltage of approximately +45 volts. The divider action of R(1), R(2) and R(5) places a positive potential at point B which in turn causes a positive potential at the base of the transistor to latch it in its off condition. The neon is now i...