Browse Prior Art Database

Circuit Breaker

IP.com Disclosure Number: IPCOM000096356D
Original Publication Date: 1963-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Erdman, BK: AUTHOR

Abstract

This circuit provides over-current protection for load 12. Normally, current flows from the +30 volt source through Zener diode 20 through transistor 16 and through resistor 23 to load 12. If the voltage across load 12 drops, i.e., if load 12 draws an excessive amount of current, the voltage at the base of transistor 18 is decreased turning transistor 18 on.

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 100% of the total text.

Page 1 of 2

Circuit Breaker

This circuit provides over-current protection for load 12. Normally, current flows from the +30 volt source through Zener diode 20 through transistor 16 and through resistor 23 to load 12. If the voltage across load 12 drops, i.e., if load 12 draws an excessive amount of current, the voltage at the base of transistor 18 is decreased turning transistor 18 on.

This increases the voltage at the base of transistor 16 turning transistor 16 off. The circuit is bi-stable. Once transistor 16 is turned off, it is not turned on again until load 12 is open-circuited.

Zener diode 20 and resistors 21 to 23 effectively form a bridge circuit. This bridge circuit insures that the turnon time of transistor 18, i.e. , the maximum current allowed through load 12, is independent of the current gain of the transistors.

1

Page 2 of 2

2

[This page contains 1 picture or other non-text object]