The transformers in your neighborhood, on electricity poles, or the ones connected to underground wires, usually transform high voltage of 7,200 volts to 220-240 volts of electricity to power lights and appliances such as refrigerators in homes and businesses. Some countries, such as America use different voltages in homes, such as 120 volts. Transformers cannot increase power, so if the voltage is raised, the current is proportionally lowered. If the voltage is lowered, the current is proportionally increased.