| 摘要 |
<p>A colour cathode ray tube display includes a degauss coil (1) and a switched mode power supply. The degauss coil (1) is connected in series with the input rectifier (5) of the SMPS to limit the current surge on power on but is shorted out by a switch (12), preferably constituted by a triac, after the SMPS switching transistor turns on to give substantially zero residual degauss current. Forward voltage drop across the triac can be compensated for by back-to-back diodes (13) connected in series with the degauss coil. The triac is switched under control of a signal from an auxiliary winding (11) on the SMPS output transformer (a).</p> |
