What is a DC power supply? A DC power supply is a device that supplies electric energy of fixed polarity, either positive or negative. "DC" in this context means "direct current." Direct current is an alternative to alternating current, frequently shortened to "AC." How do you wire your own residential telephone line? What is the junction box used for in homes? What qualifications are needed to repair a power supply? Power supplies take energy from a power input and deliver it to a power output. The input may originally come from batteries, fuel cells, generators, alternators, solar power converters or something else. The power supply takes this energy and gives it to an output, referred to as an electrical load. A DC supply can be powered by either a DC source or an AC source. Learn more about Electrical How do you change a light switch? Changing a light switch involves disconnecting the power supply to the switch and removing the old switch using an insulated screw driver.

How do you read an electrical ladder diagram? To read an electrical ladder diagram, first identify the two rails that signify the supply power, and then locate the rungs that portray all of the control... How do you install a two-way electrical switch?central air conditioning units mobile homes To install a two-way electrical switch, disconnect the power supply to the switch line, prepare the installation location and the power supply wires, and a...ac/heat unit cost What are tips for troubleshooting an electric fireplace in need of repair?ac power supply specifications To troubleshoot an electric fireplace, the first thing to do is check the power, as there may be an issue with the power supply. To do this, use a voltage ...

How do you test a coil pack? Are copies of the 2008 National Electrical Code available for free? What are some common color code meanings on electric wiring charts? What is a free medical power of attorney form specific to the state of Connecticut? How do you light a bookcase? What is the best bathroom exhaust fan?What is DC (direct current)? Part of the Electronics glossary: See also Ohm's Law. DC (direct current) is the unidirectional flow or movement of electric charge carriers (which are usually electrons). The intensity of the current can vary with time, but the general direction of movement stays the same at all times. adjective, the term DC is used in reference to voltage whose polarity never reverses. In a DC circuit, electrons emerge from the negative, or minus, pole and move towards the positive, or plus, pole. Nevertheless, physicists define DC as traveling from plus to minus. Direct current is produced by electrochemical and photovoltaic cells and

In contrast, the electricity available from utility mains in most countries is AC (alternating current). Utility AC can be converted to DC by means of a power supply consisting of a transformer, a rectifier (which prevents the flow of current from reversing), and a filter (which eliminates current pulsations in the output of the rectifier). Virtually all electronic and computer hardware needs DC to function. Most solid-state equipment requires between 1.5 and 13.5 volts. demands can range from practically zero for an electronic wristwatch to more than 100 amperes for a radio communications power amplifier. Equipment using vacuum tubes, such as a high-power radio or television broadcast transmitter or a CRT (cathode-ray tube) display, require from about 150 volts to several thousand volts DC. Posted by: Margaret RouseWhat is alternating current (AC)? Part of the Smart grid glossary: Also see current, voltage, and direct current. In electricity, alternating current (AC) occurs when charge carriers in a conductor or semiconductor periodically reverse their direction of movement.

Household utility current in most countries is AC with a frequency of 60 hertz (60 complete cycles per second), although in some countries it is 50 Hz. The radio-frequency (RF) current in antennas and transmission lines is another example of AC. An AC waveform can be sinusoidal, square, or sawtooth-shaped. Some AC waveforms are irregular or complicated. An example of sine-wave AC is common household utility current (in the ideal case). Square or sawtooth waves are produced by certain types of electronic oscillators, and by a low-end uninterruptible power supply (UPS) when it is operating from its battery. Irregular AC waves are produced by audio amplifiers that deal with analog voice signals and/or music. The voltage of an AC power source can be easily changed by means of a power transformer. This allows the voltage to be stepped up (increased) for transmission and distribution. High-voltage transmission is more efficient than low-voltage transmission over long distances, because the loss caused by conductor resistance decreases as the voltage increases.

The voltage of an AC power source changes from instant to instant in time. The effective voltage of an AC utility power source is usually considered to be the DC voltage that would produce the same power dissipation as heat assuming a pure resistance. The effective voltage for a sine wave is not the same as the peak voltage . To obtain effective voltage from peak voltage, multiply by 0.707. To obtain peak voltage from effective voltage, multiply by 1.414. For example, if an AC power source has an effective voltage of 117 V, typical of a household in the United States, the peak voltage is 165 V. Nikola Tesla, a Serbian-American scientist, electrical engineer, and inventor, developed the alternating-current (AC) electrical system, as well as radio, the Tesla coil transformer, wireless transmission, and fluorescent lighting. A power supply is a hardware component that supplies power to an electrical device. It receives power from an electrical outlet and converts the current from AC (alternating current) to DC (direct current), which is what the computer requires.

It also regulates the voltage to an adequate amount, which allows the computer to run smoothly without overheating. The power supply an integral part of any computer and must function correctly for the rest of the components to work. You can locate the power supply on a system unit by simply finding the input where the power cord is plugged in. Without opening your computer, this is typically the only part of the power supply you will see. If you were to remove the power supply, it would look like a metal box with a fan inside and some cables attached to it. Of course, you should never have to remove the power supply, so it's best to leave it in the case. While most computers have internal power supplies, many electronic devices use external ones. For example, some monitors and external hard drives have power supplies that reside outside the main unit. These power supplies are connected directly to the cable that plugs into the wall. They often include another cable that connects the device to the power supply.

Some power supplies, often called "AC adaptors," are connected directly to the plug (which can make them difficult to plug in where space is limited). Both of these designs allow the main device to be smaller or sleeker by moving the power supply outside the unit. Since the power supply is the first place an electronic device receives electricity, it is also the most vulnerable to power surges and spikes. Therefore, power supplies are designed to handle fluctuations in electrical current and still provide a regulated or consistent power output. Some include fuses that will blow if the surge is too great, protecting the rest of the equipment. After all, it is much cheaper to replace a power supply than an entire computer. Still, it is wise to connect all electronics to a surge protector or UPS to keep them from being damaged by electrical surges. Updated: January 28, 2009 TechTerms - The Tech Terms Computer Dictionary This page contains a technical definiton of Power Supply.