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你所说的使用220V但电流限制0.7mA是哪类的产品?在IEC 60950-1标准的LCC章节定义中,电压并不是最终决定因素,而是需要考量该电压的环境就是:与LCC电路的连接须符合Clause 2.4.3前提下,该LCC电路的分类和测量方式下不超过Clause 2.4.2规定限值的,才是人体可以直接触摸的。9 K3 S Q d: G9 H$ F! [9 E
注:要考虑测量时使用2000欧无感电阻、考虑电压的频率、还有该电路的电容量这些必不可少的因素。 \% h$ Q% P$ V, `4 D4 R/ W
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2.4 Limited current circuits
; Y; U; {% D: o# t7 c6 N+ a- k0 O2.4.2 Limit values
! |( H! c+ G: ~/ _/ ~+ w* lFor frequencies not exceeding 1 kHz, the steady-state current drawn through a non-inductive4 v9 ~2 w1 z7 v2 T. h6 O6 t7 V
resistor of 2 000 Ω ± 10 % connected between any two parts of a LIMITED CURRENT CIRCUIT, or4 \( H* L" |( N
between any such part and earth (see 1.4.9), shall not exceed 0,7 mA peak, or 2 mA d.c.
6 F" V& a' Q$ G/ _% aFor frequencies above 1 kHz, the limit of 0,7 mA is multiplied by the value of the frequency in
" J7 h/ P2 A% Z$ y: T' @kilohertz but shall not exceed 70 mA peak.7 K: ?5 Z0 m8 @2 ?0 g' a0 S& ~. q
Alternatively, it is permitted to use the measuring instruments of Annex D instead of the noninductive
4 l0 }1 j- ?7 b& ?. `" p# @resistor of 2 000 Ω ± 10 % mentioned above.# j0 L) i5 ^' J8 ]
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2.4.3 Connection of limited current circuits to other circuits2 W6 x( {% L$ U1 N' D; L
LIMITED CURRENT CIRCUITS are permitted to be supplied from or connected to other circuits,
* @7 [4 i! U% a0 d7 A I2 Y* B- V6 cprovided that the following conditions are met:/ s9 X$ I) ?0 i9 ~1 I6 V
− the LIMITED CURRENT CIRCUIT meets the limits of 2.4.2 under normal operating conditions;
$ }; K% G) ^8 { [3 ?9 v: g− the LIMITED CURRENT CIRCUIT continues to meet the limits of 2.4.2 in the event of a single
# a% x% N9 A: D) {% s) Rfailure of any component or insulation in the LIMITED CURRENT CIRCUIT, or of any component/ Z7 A9 ]" n3 e
or insulation in t he other circuit to which it is connected.
7 B! Q# f8 p/ T# `/ q4 N! x! e/ lIf a LIMITED CURRENT CIRCUIT is connected to one or more other circuits, the LIMITED CURRENT( Q; M/ A6 q! h/ Q$ N# y
CIRCUIT is that part which complies with the requirements of 2.4.1.
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在IEC 60950-1的限流电路(也就是LCC)的一般适用情形:5 o! b) G- F& X, {8 |7 G
某种高电压输出的电路,该电路在设计上能保证在正常和单一故障条件下,从电路流出的电流都是非危险的电流。通俗的讲法是,该电路虽然电压高但人是可以直接触摸的。 |
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