After closing the switch why can't a current through the LED and the coil at the same time, and only a short light LED after flows from the coil, the LED goes out? Thank you very much!

CodePudding user response:

Element resistance, flow back from the coil, LED out, because the coil has energy storage effect, early short light LED

CodePudding user response:

Key points: the rate of change! Through low inductance, resistance, high frequency switch points on the instantaneous inductance moment will produce counter electromotive force impeding an electric current passes through, this time from this way to the lamp, lamp current, circuit then slowly stability, inductive impedance will decrease to close to short circuit, current from passing through the inductance, so the light go out

CodePudding user response:

Order to current can't on both ends of the inductance, so first through the led, led a short light; The switch is off, after under the inductor current is positive on the negative, inductance is equal to the voltage source, diode reverse ended, so the led out