| 摘要 |
<p>The invention relates to a circuit arrangement for operating a lamp (LA) comprising means (X) for generating an alternating current, a load branch (B) coupled to the means, provided with a series circuit (Y) comprising terminals (K1, K2) for holding the lamp, interconnected by first capacitive means (C1), and a current sensor (SE). According to the invention, the circuit arrangement in addition comprises a second branch (C), shunting the series circuit (Y), comprising a series arrangement of second capacitive means (C2) and an impedance (R2). The ratio of the impedance value of the impedance (R2) to the impedance value of the current sensor (SE) is chosen as the same as the ratio of the amplitude of the current through the first capacitive means (C1) to the amplitude of the current through the second branch (C) during lamp operation. Means (II), forming part of means (I) for controlling the power consumed by the lamp, are coupled to the current sensor (SE) and the impedance (R2) for generating a signal which is a measure for a difference between the voltage across the current sensor and the voltage across the impedance, the signal forming a measure for the lamp current over a wide range of powers consumed by the lamp.</p> |
