Title:
FIRE SENSOR
Document Type and Number:
Japanese Patent JP3893797
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce the cost and size of a fire sensor by using a parallel combined resistance of a low temperature linearizing resistance and a high temperature linearizing resistance being thermistor temperature characteristic linearizing resistances as a current limiting resistance for a fire detection display element.
SOLUTION: The parallel combined resistance of the low temperature linearizing resistance R1 and the high temperature linearizing resistance R2 being thermistor temperature characteristic linearizing resistances is used as the current limiting resistance for the fire detection display element 7. Namely the parallel combined resistance of both the resistances R1, R2 is used as the current limiting resistance for the display element 7 and a microcomputer 3 having four ports PORT1 to PORT4 is used to constite the fire sensor. Since the parallel combined resistance of the resistors R1, R2 is used instead of a conventional light emitting diode current limiting resistance and a current limiting resistance for a fire detection display element used for a conventional fire sensor is eliminated, the fire sensor can be made low in cost and small in size.
Inventors:
Masashi Fukuda
Shoichi Oka
Takeshi Wada
Yasuyuki Kawano
Shoichi Oka
Takeshi Wada
Yasuyuki Kawano
Application Number:
JP14900599A
Publication Date:
March 14, 2007
Filing Date:
May 28, 1999
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS,LTD.
International Classes:
G08B17/06; (IPC1-7): G08B17/06
Domestic Patent References:
| JP11045384A | ||||
| JP2000097783A | ||||
| JP5077822U | ||||
| JP5055290U |
Attorney, Agent or Firm:
Junji Ando