A repulsion type ammeter when used on A.C circuit reads
A repulsion type ammeter when used on A.C circuit reads R.M.S value of the current.
In a repulsion type ammeter, a coil carrying the load current is placed at right angles to a fixed coil that carries a current proportional to the voltage being measured.
The interaction between the two fields produces a repulsive force that deflects the pointer. Since the force is proportional to the square of the RMS value of the current, the instrument can be calibrated to read the RMS value directly.
However, it is important to note that repulsion type ammeters are not commonly used for AC measurements due to their complexity and cost compared to other types of AC ammeters, such as moving iron and electrodynamometer types.