【单选题】The types of short-circuit in three-phase system are three-phase short-circuit, two-phase short-circuit, two-phase short-circuit grounding and single-phase short-circuit grounding. When the three phases of the system are short-circuited, they are still in the symmetrical stated. Other types of shorted circuit are asymmetric short circuit. Which of the following types is a symmetrical short circuit? A. Single phsae ground short circuit B. Three phase short circuit C. Two phase short circuit D. Two phase ground short circuit

short circuit

The resistance value is infinite, the current passing through the resistance is always zero, and the voltage depends on the external circuit, then it is called as the short circuit state.

The value of drain current is always （ ） the value of the short circuit drain current IDSS for a given JFET.

Please answer this question. A: Short circuit protection B: Overload protection. C: Under voltage protection. D: Thermal relays protection.

When the secondary side of the electromagnetic current transformer is in normal operation, it is close to ( ) state. A: Overvoltage B: Open C: Short circuit D: Under voltage

When two two-terminal networks are equivalent, they are equivalent to ( ). A: external circuit B: internal circuit C: external circuit and internal circuit D: neither external circuit nor internal circuit

布线层的规则设置在以下哪一个规则项中?[br][/br](1.0) A: Clearance B: Short Circuit C: Routing Width D: Routing Layers

PCB的英文全称是 A: Printed Circuit Board B: Play Circuit Board C: Printed Circuit Box D: Play Circuit Box

Microcontroller minimum system circuit is the microcontroller can work the smallest circuit, generally including the clock circuit and reset circuit.