DSH 755 measurement frequency of Limited Current Circuits (LCCs) capacitance

小米

广东安规检测
有限公司提供：

小型摆管淋雨试验机

IPX5X6X7喷水试验机

1000L恒温恒湿箱

各种试验指现货

可程式恒温恒湿试验箱

水平垂直燃烧机

自动卷线器试验机

耐划痕试验机

各种灯头量规现货

灼热丝试验机现货

GB1002插头量规

IPX1-X7淋雨现货

IEC61347/UL935镇流器热试验箱

灯具防风罩

IK冲击试验机

UL498插头插座量规

VDE0620插头插座量规

稳定性试验台

家电温升测试角

针焰试验机现货

热电偶焊机现货

家电125mm试验指

E12灯头量规

无绳壶无绳电熨斗插拔寿命试验机

IEC60335试验指甲

DSH 755 + g$ l$ M! ~7 f( R& x, T: N3 d + _3 V5 w9 L! a

measurement frequency of Limited Current Circuits (LCCs) capacitance

2.4

60950-1(ed.1) & 60950-1(ed.2) 8 Q4 p- |& N- C( n2 J

/ I( [) {( T. k7 @

Question:
+ l: m4 @0 g0 _4 ^8 X( H$ D, G! HWhen measuring the circuit capacitance according to clause 2.4, what frequency should be used, 1kHz, the measured frequency of the circuit or another frequency?

Proposal:

For frequencies not exceeding 1kHz, the circuit capacitance shall be measured at a frequency of 1kHz.

For frequencies above 1kHz, the circuit capacitance shall be measured under the actual circuit frequency or the nearest frequency point of the measuring equipment.

Decision:

LCC limit values per 2.4.2 typically are applied to two different types of circuits, those

providing:

(a) steady state current, or

(b) capacitively driven current.

In a single product, one or multiple measurements may be required based on the type

of individual circuits involved.

·          For circuits with steady state current of a single frequency, a measurement through a 2000 ohm resistor is conducted. There is no capacitance determination.

·          For circuits with steady state current of multiple/complex frequencies, a measurement using one of the measurement instruments of Annex D is conducted. There is no capacitance determination.

·          For a circuit with a capacitance driven current, such as found in a lamp driver circuit, where the current typically is driven by a ‘single’ capacitor, the circuit capacitance can be determined via either the marked nominal capacitor rating or measurement of the single capacitor via LCR measurement equipment. For circuits that have capacitance driven currents, there are no additional current measurements. It is purely a capacitance determination or measurement, with maximum capacitance defined per 2.4.2, based on the maximum Working Voltage of the circuit.