| 摘要 |
<p>1347793 Discharge tubes PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 1 Nov 1971 [4 Nov 1970] 50643/71 Heading H2H [Also in Divisions G2 and H1] An electric discharge in a gas and/or vapour discharge tube 1, Fig. 1, having an external ignition electrode 12 is initiated by means of a piezoelectric element 2. Operation of the element 2 gives rise to a voltage which triggers an SCR 6 and the resulting voltage across the secondary winding 11 of a transformer serves to ignite the discharge (which may be stopped by discharging a capacitor 15 charged from the supply 13). The device may be used on a camera 40, Fig. 4, whose shutter 41 is linked to a percussion device 42 which operates the piezoelectric element 44 in an adaptor 43 so as to ignite either an electronic flash lamp 46 or a high-voltage combustion flash bulb. 48. The arrangement may be such that the adaptor may be omitted (Fig. 3, not shown) and the element may be incorporated in the camera itself (Fig. 5, not shown). Alternatively, the element may be incorporated in a rotary switch 100, Fig. 6 (not shown), for the ignition of a high-pressure sodium vapour discharge lamp (81); the element (103) is connected to the ignition electrode (95) so that rotation of the switch closes the circuit and at the same time causes the element to be struck to provide the ignition voltage.</p> |
