The Effective Voltage for a Sinusoidal Alternating Current
- The maximum potential difference supplied by an a.c source is known as the peak voltage VP.
- The effective potential difference for an a.c is equal to the potential difference of an alternating current if both results in the same heating effect.
- The effective potential difference for a.c is known as the root mean square voltage (r.m.s) of the a.c. and is given y the following equation:
- The root-mean-square (r.m.s) value of an alternating current is the value of the steady direct current which produces the same power in a resistor as the mean power produced by the alternating current.
- The r.m.s current is the effective value of the alternating current.
- The r.m.s. current can be calculated by using the following equation:
Example 1
The diagram above shows a graph of potential difference, V against time, t of an alternating current. Find the Vr.m.s. of the power supply.
Answer:
Example 2
The diagram above shows the waveform of an a.c. supply. What is the root mean square value of the current?
Answer: