Title:
ELECTROMAGNETIC ALARM
Document Type and Number:
Japanese Patent JP2003122369
Kind Code:
A
Abstract:
To prolong the life of an alarm by preventing the wear of contacts of an electromagnetic alarm and simultaneously to suppress the generation of noise to the outside of the alarm.
The current to a coil (11) for vibrating a diaphragm (1) by an electromagnetic effect is controlled by using a power MOS type FET (12) and a transistor (TR) 10 for controlling this FET (12) by a weak current is disposed. Only the current flowing in the TR (10) is passed to the contacts (5a) and (5b) and therefore the generation of sparks is suppressed.
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Inventors:
NAKAZATO TAKAYUKI
NAKAZAWA KATSUMI
NAKAZAWA KATSUMI
Application Number:
JP2001317992A
Publication Date:
April 25, 2003
Filing Date:
October 16, 2001
Export Citation:
Assignee:
MIYAMOTO KEIHOUKI KK
International Classes:
G10K9/15; G10K9/12; (IPC1-7): G10K9/15; G10K9/12
Attorney, Agent or Firm:
Satoshi Watanabe