Alternating current changes in magnitude as well as direction. The maximum value of the alternating current is called the peak value. It is denoted by $$I_{0}$$. The square root of mean square value of current is called the ‘effective value’ or ‘rms value’ of current. The two are related by $$ ext{Effective value, }I_{eff} = dfrac{I_{0}}{sqrt{2}}$$