| 摘要 |
THE LINE-SWEEP POWER CIRCUIT IS OF THE KNOWN TYPE, IN WHICH THE BASE CURRENT OF THE SWITCHING TRANSISTOR (TP) IS AUTOMATICALLY MAINTAINED BY A POSITIVE FEEDBACK PROVIDED BY A WINDING (L2) OF THE EHT TRANSFORMER. THIS CIRCUIT IS SYNCHRONIZED BY A SIGNAL TRANSMITTED BY AN OPTOCOUPLER (DE-TC).THE DUTY FACTOR OF THE CONTROL SIGNAL TRANSMITTED BY THE OPTOCOUPLER IS MODIFIED IN A PROGRESSIVE MANNER DURING THE TRANSITIONS OF A START SIGNAL (RC) SO AS TO INTERRUPT THE CONDUCTANCE OF THE POWER TRANSISTOR AT AN EVER EARLIER INSTANT.THIS MAY BE OBTAINED, FOR EXAMPLE BY MEANS OF AN INTEGRATOR (4, 8)TO WHICH THE LOAD RESISTOR (R2) OF A TRANSISTOR (T0) WITH AN OPEN COLLECTOR IS CONNECTED, WHICH IS DRIVEN BY A LINE SYNCHRONIZING SIGNAL.APPLICATIONS: TELEVISION, MONITORS.(FIG. 2)
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