How to Transform AC into DC

It’s not difficult to distinguish alternating current from direct current. By observing how some electricity-powered appliances in your home function, you can tell which ones use AC or DC by their distance from the power source. Those plugged farther away from the power source use AC, while those connected directly to the source use DC.

You television, for instance, uses AC because it’s powered through a plug that goes into the wall. The best example of a device in your home that uses DC is your flashlight. It’s not plugged anywhere and gets its power from the batteries inside it, which produces DC. You can simply assume that any appliance or device that gets its power from batteries uses DC.

Meanwhile, certain devices in your home use both DC and AC. Your laptop and cellphone, for instance, use DC but have to be plugged into an AC source to recharge. If you’ve read about the basics of electricity, you know that only DC can be stored, so why charge a battery from an AC source?

Well, this is because the charger you plug into the wall consists of rectifiers, whose main function is to transform AC into DC as they enter the batteries of your devices. These rectifiers, however, cannot transform the dangerous currents coming from the electrical source and flowing directly into the charger, which is why the charger also has a current transformer in it.