Electrical circuit for pre-heating lamp e.g. halogen lamp, has switching unit for switching pre-heating current, where voltage at lamps is zero and lamps are switched off when current in pre-heating current circuit exceeds threshold value
摘要
<p>The circuit has a diode (D1) for disconnecting an operating voltage. A switching unit is provided for switching a pre-heating current and a control is provided for the switching unit. Voltage at lamps is zero and the lamps are switched off when current flowing into a pre-heating current circuit is maximum and exceeds a threshold value. The pre-heating current is defined so that the circuit is short-circuit proof.</p>
