Title:
DIMMER
Document Type and Number:
Japanese Patent JPH1145785
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a dimmer having little dispersion of a dimming characteristic. SOLUTION: This dimmer is provided with a triode AC switch TRC which is a bidirectional three-terminal thyristor forming a closed circuit together with a series circuit of a commercial power supply Vs and an illumination load La. A diode bridge DB which is a full-wave rectifier rectifying the commercial power supply Vs is connected between the main terminals of the triode AC switch TRC. A time constant circuit constituted of a resistor R5 and a capacitor C1 is connected between the DC output terminals of the diode bridge DB. A series circuit of a variable resistor VR and a resistor R4 constituting a reference voltage generating circuit is connected between the DC output terminals. The base potential of a transistor Q1 connected with an emitter to the connection point of the resistor R5 and the capacitor C1 is determined by the divided voltage across the variable resistor VR. When the emitter potential becomes higher than the base potential by about 0.6 V, the transistor Q1 is turned on and feeds a trigger signal to the gate of the triode AC switch TRC.
Inventors:
MUKAI TATSUYA
Application Number:
JP21827397A
Publication Date:
February 16, 1999
Filing Date:
July 28, 1997
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS LTD
International Classes:
H05B37/02; H05B39/00; (IPC1-7): H05B37/02; H05B39/00
Attorney, Agent or Firm:
Keisei Nishikawa (1 person outside)
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