Alternating Current and Power Supplies

Most people have heard that the electrical current that comes from the wall receptacle is known as “alternating current.” Rapidly alternating the polarity of an electric current was conceived as far back as the 1880’s. By generating AC electricity, transformers could be utilized to easily either step-up or step-down voltages as desired.

The advantages were that at high voltages (thousands of volts), electricity could be transmitted far and wide with little line-loss to heat within the transmissions lines. Then, when received at the area of its use, the electrical voltage could be stepped-down through transformers and to safely usable voltages such as 120 VAC or 220 VAC. This method was the practical beginning of electricity distribution throughout the world.

Most of our modern plug-in appliances are designed to utilize the AC power directly from the wall sockets, or receptacles. Once entering the appliance, TV or other device, the AC power is distributed to the various internal mechanisms, motors, lights, heating coils and the like, within the device.

This works well for larger devices, which are designed to use the higher voltage AC current that comes from the wall. However, many modern, electronic devices are much more easily and safely designed to use lower voltages than a simple plug and cord can provide.

These smaller devices include MP3 players, answering machines, computer speaker systems, and boom boxes, as well as battery chargers for your cell phones, Bluetooth devices, electric toothbrushes, etc.

For these low-voltage devices, manufacturers provide a common device known as a power supply. A power supply usually looks like a little black box that plugs in at the wall. A small wire, or pair of wires, comes from the box and has a special plug that mates with your electronic device. The job of the power supply is to convert the higher voltage at the wall socket down to a lower voltage that the electronic device can safely use.

A backup power supply, or power supply backup, sound similar, but are much more complex and have an entirely different job. These devices contain large batteries and complex electronic circuitry, which provide power should the household electricity be interrupted. A vitally important computer that must remain running during a blackout would be a perfect candidate for a power supply backup. Often these units are known as UPS’s, or uninterruptible power supplies.

The miniature power supplies in the first group are so common now that a word of caution is in order. You may already find many of them in your home or place of work. Because they are made specifically for the devices that they are shipped with, you would never want to mix one power supply up with another, then plug it into the wrong electronic device. The connectors are often similar, and confusion can be easier than you might think. So, to prevent doing irreparable damage to your valuable electronics, mark all new power supplies with the names of the devices that they are intended for.

DCPowerSupplies.org