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High Current Generator Circuit

IP.com Disclosure Number: IPCOM000093341D
Original Publication Date: 1967-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Patlach, AM: AUTHOR

Abstract

The circuit delivers a current pulse of high power and predetermined duration to load RL through silicon controlled rectifier SCR. Capacitor C serves both as a timing and commutating capacitor. The circuit is triggered by the application of positive pulses between terminals 1 and 2. Prior to the application of such a pulse, SCR is not conducting nor is unijunction transistor UJT. Transistor Q is conducting as a result of supply voltage E producing a current flow through RL, a low resistance. Terminal B is then at ground and terminal A is close to the supply voltage. When a pulse is applied between terminals 1 and 2, SCR is turned on to supply current through the load and the voltage at A drops to about one volt. The emitter voltage of transistor Q is then higher than the base and the transistor cuts off.

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High Current Generator Circuit

The circuit delivers a current pulse of high power and predetermined duration to load RL through silicon controlled rectifier SCR. Capacitor C serves both as a timing and commutating capacitor. The circuit is triggered by the application of positive pulses between terminals 1 and 2. Prior to the application of such a pulse, SCR is not conducting nor is unijunction transistor UJT. Transistor Q is conducting as a result of supply voltage E producing a current flow through RL, a low resistance. Terminal B is then at ground and terminal A is close to the supply voltage. When a pulse is applied between terminals 1 and 2, SCR is turned on to supply current through the load and the voltage at A drops to about one volt. The emitter voltage of transistor Q is then higher than the base and the transistor cuts off. Terminal B then goes positive as capacitor C charges through Rt and SCR. The peak voltage of UJT is reached after a time determined by Rt and C. It then fires causing terminal B to return to ground. This change in voltage is transmitted through capacitor C to lower the voltage at terminal A sufficiently to turn off SCR. The value of C is selected to maintain terminal A at the lower voltage for a time sufficient to ensure that SCR is turned off.

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