What Power Supply Do I Have?

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You may be asking yourself: ‘What power supply do I have?’ But where would you find that information? Fortunately there are ways to find out. In this article you will discover how to identify your power supply as well as how to find its wattage and efficiency rating. It is easy to determine if you are using the correct power supply if you know how to check the power supply model number. Read on to learn more.

Identifying a power supply

Identifying a power supply is an important task when dealing with electricity-using devices. Fortunately there are various methods available to perform this task. One such method is the use of a voltage divider. This circuit divides the voltage from the power source into the appropriate identification voltage. It is possible to determine whether a power supply is an AC adapter a power brick or an internal silver box that houses the computing device.

Depending on the type of power supply the identification circuit may be composed of transistors capacitors and resistors. Each one has a certain resistance value and the resistors are numbered. Transistors are identified by letters or numbers such as Q2 Q3 Q5 Q6 Q7 and Q8. These devices may be bipolar junction transistors junction gate field-effect transistors metal-oxide semiconductor field-effect transistors and many other types of transistors.

Checking a power supply’s wattage

When you buy a power supply make sure to pay attention to its wattage rating. It should be listed next to the name or model number. The wattage is an important measurement as it reflects the amount of power the unit is capable of supplying. If the power supply only provides a small amount of power the rating may not be enough to run the system. Instead look for a power supply that can support a greater amount of load a higher number and a lower one.

You can use software to test the output of your power supply. Try the freeware SpeedFan. The program will report temperatures and voltages and will also let you check your computer’s performance. Before running the tests make sure your power supply is turned on and connected to a 20/24-pin connector. If you are unsure of the connection try plugging a paperclip into the green pin on the 20/24-pin connector. Then plug in a multimeter and connect the negative probe to the ground pin on the power supply. If the multimeter does not light up you should try other troubleshooting steps.

Checking a power supply’s efficiency rating

The first step to check a power supply’s efficiency rating is to determine its efficiency at a specific load. You can perform this test using the Kill-A-Wall Meter. Then connect a working motherboard to the power supply and turn on the machine. Once the machine is running run the efficiency test at a specific load. The power supply should meet or exceed the specified load. If it fails consider replacing it.

To check a power supply’s efficiency you will need to measure the total power the unit delivers versus the total amount of power it consumes. Efficiency ratings are expressed in percent and are calculated by measuring the output power to the input power. Ac/dc power supplies have nonlinear efficiency versus load curves so efficiency tests must be performed at several different load levels. Most Efficiency Star tests use 100% load 75% load and 50% load. European CoC Ver 5 Tier 2 standards require testing at 10% of the load. During a typical efficiency test the power supply first runs at full load for 30 minutes then monitors ac input power for five minutes.

Checking a power supply’s model number

First check the label on the power supply unit itself. This label will be written in the largest font and will have information about the power supply. If you have a transparent case you may not have to touch the sticker to retrieve this information. If you do you can take a high-quality photo of the label and zoom in if necessary. If you don’t have a digital camera you can use Google to find the model number and other information.

If you have a power supply tester connect it to the motherboard’s connector. You should find many pins and colorful cords. Then perform a paper clip test to determine whether it is functioning properly. Simply bend a paper clip into a u-shape and insert it into the pin leading to the green or any of the black wires. If there are multiple wires with different colors insert the paper clip into pins 4 and 5 as well.

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