Below is a list of Step Down Transformers manufacturers from Foster City, California. Step down transformers have the power to convert higher voltages to lower voltages by means of transferring electrical energy through two coil stages, the second coil stage having fewer coil windings. Power outlet voltages vary depending on geographical location. The two commonly used outlet voltages are 220 volts and 110 volts. This voltage difference is an important consideration for people traveling between countries with different outlet voltage standards.