Understanding Back EMF: Effects on Parallel and Series Electrical Circuits

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When an electric drill is turned on, it causes a surge of current that briefly dims the lights in parallel circuits. This flickering occurs due to the initial demand for power as the motor starts. Once the motor reaches operational speed, back EMF is generated, which opposes the current flow and reduces the overall current in the circuit. In series circuits, the lights would dim and remain dim due to the constant load. Understanding back EMF is crucial for analyzing how electrical devices affect circuit performance.
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Ex:At home, you plug an electric drill into an electrical outlet and turn it on. At the moment you turn on the drill, the lights in the room(wired in parallel to the drill) flicker and dim briefly, but then return to normal after a moment.

notice that the example is wired in parallel, but in series lights will just get dim and stay the same.

what had happened in both of the case and how can i relate this to back emf?
 
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When you turn the electric motor on, there is a surge of current, dimming other lights.
When the motor gets up to speed, there is a back EMF in the circuit which reduces the current through the motor.
 
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