AC current applied to a resistance only

 


1) Let an alternating voltage is applied to a resistance R as shown in the diagram.



2) Suppose the alternating emf is 







 



Now from ohm’s law, We know


 


This is the alternating current that flows through the circuit due to alternating voltage  applied in the circuit.



where





This diagram is the variation of emf and current with angle 


Note: In this diagram the current I is lower than the emf  due to resistance R.

 

 

  

Phasor diagram of resistor

in an AC circuit:

 

 

In phasor diagram the current (I) & voltage has same angle, for a resistance in AC circuit.