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Patent Searching and Data


Title:
SHORT CIRCUITE DETECTION AND DISPLAY CIRCUIT
Document Type and Number:
Japanese Patent JP2005026107
Kind Code:
A
Abstract:

To solve a problem of display misinterpretation caused by blinking of a short circuit display element in normal time by a ripple voltage of a D.C. power supply while stably securing an original short circuit display function.

This short circuit detection and display circuit is so structured that the output of a zero-phase current transformer 2 interlaid in a main circuit 1 is inputted to a ground leakage detection circuit 2 and the short circuit display element 14 is lit by its output signal. The circuit comprises: an output circuit 7 including a switching element 9 turned on by the output signal of the short circuit detection circuit; a snubber circuit 10 connected in parallel with the switching element; and a short circuit display circuit 13 composed by connecting a current limit resistor 18 in series to the display element 14; and is supplied with D.C. output obtained from an A.C. power source 4 through a rectifying circuit 5 and a smoothing capacitor 6. A zener diode 18 having a zener voltage corresponding to a ripple voltage superimposed on the D.C. output is connected in series to the short circuit display element to reduce a current flowing through the short circuit display element in a normal time, so that its blink is prevented from being viewed.


Inventors:
HASEGAWA KIYOSHI
Application Number:
JP2003191020A
Publication Date:
January 27, 2005
Filing Date:
July 03, 2003
Export Citation:
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Assignee:
FUJI ELEC FA COMPONENTS & SYS
International Classes:
H01H83/02; (IPC1-7): H01H83/02
Attorney, Agent or Firm:
Masaharu Shinobe