Supply network for mercury vapour discharge lamp - uses second inductor and capacitor in lamp supply to induce voltage transients on tube voltage waveform to allow lower voltage control

摘要

The electric supply control network has an extra capacitor (C2) and inductor (L2) connected between the usual capacitor (cl), inductor (L1) network, and the discharge tube (TD). The extra inductor (L2) and capacitor (CZ) introduce transient voltage spikes on the tube voltage versus time curve. These spikes provide a striking voltage which allows supply voltage to be reduced to approximately 50% of the nominal value and the light output of the tube to be correspondingly reduced. The values of second capacitance and inductance lies within set bounds if the required voltage overshot is to be obtained. For the capacitor the range is between 0.005 and 0.02 P and for the inductor LC is between 25 and 100 where C is capacitance in micro farad; L inductance in millihenries and P the rated power of the discharge tube in watts.