| 摘要 |
PURPOSE:To obtain a high pressure metal vapor discharge lamp with short insulation breakdown time and also short arc discharge transfer time and excellent startability by impressing pulses with low generation frequency but high peak value and pulses with high generation frequency but low peak value alternately together with the distributed power supply voltage between the electrodes of a light emitting tube. CONSTITUTION:A series circuit of a current-limiting resistor 5a and a rectifying device 6a and a series circuit of a current-limiting resistor 5b and a rectifying device 6b are connected in parallel so that the rectifying device 6a and 6b may be inversely paralleled, and a series circuit of such a parallel circuit, a normally closed type bimetal switch 7 and a glow starter 8 is connected with a light emitting tube 2 in parallel. In case that the current-limiting resistor 5a is, for example, 300OMEGA, the current-limiting resistor 5b 1,200OMEGA and the above-mentioned circuit is impressed with the distributed alternating-current power supply voltage, the voltage waveform generated between A and B is such that pulses with high generation frequency but low peak value and pulses with low generation frequency but high peak value are alternately superposed on the commercial alternating-current power supply voltage each half cycle, after the warm-up time of the glow starter 8. This is a phenomenon caused for the reason that the switching currents of the glow starter are different each half cycle by the action of the current-limiting resistor 5a and 5b, and thereby the voltage waveform suitable for both insulation breakdown and arc transfer can be obtained. |
