Assume now that a transformer converts high-voltage, low-current electricity transported by the wires into low-voltage, high-current electricity for use at the consumption point. If we suppose it is an ideal transformer with a voltage ratio of formula_9 (i.e., the voltage is divided by formula_9 and the current is multiplied by formula_9 in the secondary branch, compared to the primary branch), then the circuit is again equivalent to a voltage divider, but the transmission wires now have apparent resistance of only formula_12. The useful power is then: