Ayrton shunt

[3] Multirange ammeters that use this technique are more accurate than those using a make-before-break switch.

[4] Also it will eliminate the possibility of having a meter without a shunt which is a serious concern in make-before-break switches.

The voltage drop across parallel branches is always equal.

When all resistances are placed in parallel with Rm maximum sensitivity of ammeter is reached.

[5] Ayrton shunt is rarely used for currents above 10 amperes.