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用示波器测试的话,对单一频段的测试更精确,用228表测试的话,是所有频段的综合值。
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可以参考UL的测试datasheet中的备注部分:
5 f) T% R: k# \& ?/ {2.4.1, 2.4.2 - LIMITED CURRENT CIRCUIT MEASUREMENTS (con”t)
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5 t% x3 j0 H5 j* h7 {2 ]- _, B1. Measurements using the 2000 Ω resistor - for frequencies not exceeding 1 kHz, the steady-state current drawn through a non-inductive resistor of 2000 Ω connected between an accessible part of a limited current circuit and either pole of the limited current circuit or earth shall not exceed 0.7 mA peak ac, or 2 mA dc. For frequencies above 1 kHz, the limit of 0.7 mA is multiplied by the value of the frequency in kilohertz but shall not exceed 70 mA peak. This method is recommended for single frequency circuits (i.e. pure sine wave only).
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; G+ |$ ^1 R. C y: P2.Measurements using the IEC leakage current meter - the current measured between the user accessible part of a limited current circuit and either pole of the limited current circuit or earth shall not exceed 0.5 mA rms (0.7 mA pk). This method is recommended for multi-frequency circuits. |
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