| 摘要 |
A clocked current supply has a fault current detector (32) that evaluates a voltage drop occurring at an ohmic measurement resistance (25) and supplies a switching-off signal (40) to a clocked voltage transformer (5). The ohmic measurement resistance (25) is arranged in a line (24) of the clocked voltage transformer (5) through which flows the operation alternating current of the clocked voltage transformer (5) and whose frequency is the same as the frequency of a switching signal (23) that operates a power switch (16). Means, for example a low-pass (33) and/or a parallel capacitor (26) that bridges the ohmic measurement resistance (25), are provided to suppress the part of the voltage drop measurable at the ohmic measurement resistance (25) whose frequency corresponds to that of the switching signal (23). This clocked current supply is particularly suitable for operating gas discharge lamps (7) mounted for example in motor vehicles, and ensures an effective protection of persons (30) against inadvertent contact with live parts.
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