Question

In a LR circuit, can we sum potential difference of inductor & resistor to find pd of ac source?

Answer 1

you should find impedence of each element in ckt ,find node voltage ...

Answer 2

we cannot sum potential diff in RL circuit..

Answer 3

why is that?

Answer 4

You have to vector sum the Pd across the resistor and inductance to get the PD of the source, The reason is (restricting the discussion to a fixed single frequency alternating voltage source) the voltage across the resistor will be in phase with the current, but the voltage across the inductor will be 90 degrees out of phase with the current. The voltage across the two components will be the vector sum of the voltages across the individual components.