Subject: Capacitor discharge voltage measurement
Question:
The standards referenced include a test commonly referred to as a plug discharge or capacitor discharge test that involves disconnecting the product under test from the mains and measuring the residual voltage across a capacitor(s) at a specified time. The intent in each of the referenced standards is the same – measure the maximum voltage obtainable at the time specified.
(1) Each standard has a slightly different description of how the mains disconnect is made, but the intent is to disconnect at the highest voltage possible in the AC power cycle. With the advent of electronic voltage sensing switches, it is possible to disconnect at the peak voltage in the AC cycle. Using this procedure seems to be within the intent of the standards and would result in more consistent and repeatable results. Is it acceptable to perform the test this way?
(2) Good laboratory practice dictates that the voltage should be measured with a high input impedance voltmeter. For this test, some standards require the use of a voltmeter with an input resistance of 100 M 1 ± 5 M 1 in parallel with an input capacitance of 25 pF or less. For more consistent and repeatable results should this type of meter always be used for this type of test?
Decision:
(1) Yes, this method should always be used for these tests within the CB Scheme.
(2) Yes, a meter with the stated input impedance should always be used for these tests within the CB Scheme.
问题：
所引用的标准包括通常称为插头放电或电容器放电测试的试验，该试验涉及将被测产品与电源断开，并在指定时间内测量电容器两端的残余电压。每个参考标准的目的都是相同的：测量指定时间的最大电压。
（1）每个标准对如何断开电源的描述略有不同，但目的是在交流电源的最高电压下断开。随着电子电压感应开关的出现，可以在峰值电压下断开连接。这种情况似乎符合标准的意图，并且会产生更加一致和可复现的结果。以这种方式进行试验是否可以接受？
（2）规定应使用高输入阻抗的电压表测量电压。对于这项试验，某些标准要求使用输入电阻为100MΩ±5MΩ与输入电容为25pF或更小的电压表。为了获得更加一致和可复现的结果，是否应始终使用此类型的仪表用于试验？
决定：
（1）是的，该方法应始终用于CB试验。
（2）是的，在 CB 试验中应始终使用具有规定的输入阻抗的仪表。
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