Electromagnet voltage line
Electromagnet suction with lron experiments just choose a voltage and an electromagnet, no power, using the iron near electromagnet didn't reflect on the dynamometer, and then turned on the electricity is sucked again close to that with other non-ferrous material and electromagnet attraction, is less than absorption, clarify electromagnet suction with lron. It can be about dc, but about the communication circuit and magnetic circuit, is because of its parameters with time and change, their expression method and operation process has certain characteristics. These characteristics in addition to the parameters in the specialized theory respectively in the escape, electromagnet to briefly talk about several characteristics in the most basic, to help echo relevant chapters carry back in a timely manner. Alternating current communication electricity) current, and voltage magnitude and direction of the electric potential, to make periodic changes over time, while the direct current direction is always the same size. Who communication by the electric circuit is called a communication circuit. Communication circuit has the characteristics of different from dc. Now flee as follows in the dc, current through simply resistance from us. So according to the rules of the good, the dc current is equal to the size of the power supply voltage divided by resistance. In communication circuit, bundled except resistance electric current passes through, and by the electromagnetic induction of capacitive reactance inductance and static electricity. Inductive and capacitive reactance reactance. Lay in the communication of capacitive reactance is actually very small, generally can suddenly road, the reactance is equal to the impedance. So can't briefly in the communication circuit to obtain current with voltage divided by resistance. Arm as we use 220 v direct current (dc) on both ends of 10 European resistance can figure, according to the rules of ohm can immediately can calculate the circle in the flow of electric current for 220/10-22. But, assuming the same only on 220 v electric communication circle, so, because of the existence of reactance, in the secret circle after the current will be far smaller than 22 to Ann. Communication circuit, therefore, in addition to the resistance and reactance exists, is one of the primary characteristics of it. Flow in the circuit, voltage and current are constant over time changes from zero to the maximum, and decreased from maximum to farce. And then in another direction for the same changes (FIG. 2-21). Change of time is very short in we hard to conclude that a change in the calculation of transient asked f of the voltage and current. We usually don't have to be on the practical instantaneous value to indicate the size of the electric communication. Communication electricity equal dc to indicate the size of the commonly used thermal effect, known as valid communication. Such as, there are two of the same numerical pure resistance, respectively into the communication power and direct current (dc), assuming that the calories they happen, we will call this dc electricity the RMS values of the size of the communication. Communication electricity most at present is sine wave when the communication of electricity.