US 5,510,682 AGranted

Magnetism-erasing circuit for use in cathode ray tubes using a D-C power supply

AssigneeHyundai Electronics Industries Co., Ltd.

InventorTae-Jung Park

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Abstract

A magnetism-erasing circuit for use in cathode ray tubes of portable televisions or the like for erasing the magnetism from the cathode ray tubes is disclosed. The magnetism-erasing circuit includes: a) automatic trigger for an automatically generating trigger signals when a D-C supply is initially applied to the magnetism-erasing circuit, b) trigger detecting means, c) delay and second trigger means for generating second trigger pulses which are delayed by a specified time interval by the detected trigger signals from the trigger detecting means, and d) means for controlling the driving of the magnetism-coil by applying currents to a magnetism-erasing coil. The magnetism-erasing circuit of the present invention further includes manual trigger means for manually generating trigger signals under the condition where a D-C supply has already been applied to the circuit.

Claims8

Dependent claims

A magnetism-erasing circuit for a cathode ray tube, the cathode ray tube comprising a magnetism-erasing coil, the magnetism-erasing circuit being powered by a D-C power source, the magnetism-erasing circuit comprising:

a) trigger means for automatically generating a trigger signal when the D-C power source is applied to the magnetism-erasing circuit;
b) trigger detecting means for detecting the trigger signal from the automatic trigger means and for generating a first trigger output signal responsive thereto;
c) delay and second trigger means for generating a second trigger output signal that is time delayed by a predetermined time interval from the trigger signal;
d) switch means which operates responsive to the second trigger output signal from the delay and second trigger means;
and
e) means for controlling the driving of the magnetism-erasing coil, the magnetism-erasing coil driving control means being controlled by the switching means for causing current to flow through the magnetism-erasing coil for generating a magnetism-erasing magnetic field;
wherein the trigger means, the trigger detecting means, the delay and second trigger means, the switch means, and the means for controlling the driving of the magnetism-erasing coil are each powered by the D-C power source.

4 more elements

Dependencies are inferred from the claim text.