A Guide On How To Test Laptop Power Supply

A Guide On How To Test Laptop Power Supply

Your laptop is useless without power, no matter how beautiful or powerful it may be. How your laptop receives and distributes power to its components is therefore as essential as the device itself.Just like any electronic device, your laptop receives power through a power supply.

The power supply unit supplies electricity to the entire system. A power supply converts power from an alternating current (AC) source into a direct current (DC), which the system can distribute to its components for them to function.

The laptop power supply comes in the form of AC adapters. Power issues may arise, which may necessitate testing your power supply. 

How To Test Your Laptop Power Supply

You would need a multimeter for this task. A multimeter is an electrical testing tool that can measure multiple electrical parameters such as voltage, current, and resistance. It has two probes – negative and positive differentiated with red and black colors, respectively.

Follow the steps below to test your laptop power supply or AC adapter. 

  • Connect your power supply to an AC source.
  • Switch on the multimeter and adjust the settings to read DC voltage.
  • Insert your multimeter’s red probe into the power supply plug’s end.
  • Take your multimeter’s black probe and gently press it on the plug’s barrel.

Note: Use extra care to avoid contact between probes, else you’ll create a short circuit.

Your multimeter should display the voltage reading of your power supply. Most household electrical or electronicdevices allow for a 10% deviation from the standard specification. 

So, if you have readings relatively close to the voltage requirements for your power supply, then it is in good condition. Other than that, you may consider changing your laptop charger.

Note: Sometimes, you might get a negative reading on your multimeter. It could be because you have attached the probes in reverse.Double-check the polarity on your power supply’s label if this occurs and ensure your laptop can handle it.

How Your Laptop Power System Works

An internal battery powers your laptop using DC voltage.The wall socket delivers a much higher voltage AC, which the transformer and other electronics convert to a DC voltage for charging the battery.

A transformer, a rectifier, and an electronic filter make up an essential AC adaptor. The transformer converts high-voltage AC supplied by an electrical outlet to a lower voltage suitable for your laptop.A rectifier then converts AC into DC.

An alternating current is a charge flow that alternates in direction regularly (AC). As a result, the voltage level fluctuates as the current flows. Direct current (DC), on the other hand, maintains a constant current and voltage.

Caring For Your Laptop Power Supply

Frequently changing your laptop supply due to malfunction will cause you money and stress. It is therefore essential that you maintain your laptop charger to ensure continued use.

Consider the following suggestions to keep your laptop power supply in good health. 

Do not wrap your power cord tightly:

Some people are organizational freaks and tend always to wrap their power adapters too tightly to keep things orderly. Wrapping your power cord too tightly can shorten its lifespan.

Wrapping your power cords exacts undue strain on power cords’ thin copper conductors. They may break, as a result. It is best to loosely loop the power cords while changing the pattern to avoid stressing a particular section. 

Use power strips:

A power strip with a built-in surge protector is an excellent option.Power strips with surge protectors can protect your power cord while plugging in multiple devices with one outlet.

Give the transformer enough room:

A transformer has two functions: it reduces the line voltage from the wall to a level that your laptop can handle, and it transforms alternating current to direct current.

The transformer may become hot while charging. Ensure your laptop is charging somewhere with plenty of ventilation if you’re plugging it in for an extended period.

Avoid sharp edges:

Prolonged contact with sharp edges can degrade the rubber protecting your laptop power cord wires.

Whether you often move your power cord from one place to another or have a designated charging hub, ensure your setup doesn’t expose these delicate wires to sharp edges.

Keep your charger away from water:

Keep your computer and cord away from liquids as much as possible.When your laptop power cord comes into touch with water, it might cause laptopdamage and electrocution.

Troubleshooting Laptop Power Supply Problems

Sometimes you may have issues getting to shout. You may have plugged your power cable into a power source, but power doesn’t get to the laptop. Before you hurry to change your power supply, try some troubleshooting techniques.

Check your connections:

Before moving on to more advanced troubleshooting, go over the basics. Ensure you have firmly inserted the card into your laptop’s charging port. Also, double-check the wall connection ortry a different socket. Instead of using a power strip, connect directly to a wall outlet.

Connect the laptop directly to a power source by removing the battery:

Check if your laptop’s battery is still functional. Detach the battery from the laptop if it is removable?

If your device has a removable battery, detach it from the computer.

Typically, you may do this by pullingsome tabsbeneathyour laptop. Consult your manual if you’re not sure of what to do.Always turn off your laptop before you remove the battery.Detach your power cords and other accessories as well.

Hold the power button for several moments after removing the battery to clear any excess charge in the system. You can now connect the charger and switch on your laptop.

If your laptop comes on, then your battery may be faulty, and there’s nothing wrong with your power supply. Check your battery compartment for any dirt or foreign material and get rid of it.

Return the battery to the compartment. If this doesn’t fix the problem, you most likely have a dead battery that you’ll need to replace. If your laptop doesn’t have a removable battery, you can try opening up your machine and removing it yourself. 

However, you risk losing your warranty coverage from the manufacturer, and a mistake can cause you severe damage. Take your device to a technician who will assist you. 

Check the charger and the ports for compatibility:

The next thing is to check whether power is reaching the laptop. 

Check that the charger for your laptop is in the correct port. Although many laptops only have one charging connector, a newer computer may charge through USB-C.

Test all of your laptop’s USB-C ports, as some may be for data transfer. A small power icon may appear next to the charging port on some PCs.

For optimum results, use original chargers to power your laptop.Fake chargers can cause long-term damage to your battery.

Your laptop may charge slowly or not at all if you use a third-party model that does not use the appropriate wattage. This problem is common with USB-C.

Check charger and ports for any damage:

Even if you checked for cable connection problems earlier, you could look over the power cord again.Examine the whole length of your laptop’s power line for any damage or bulging areas.

If you perceive a burning smell in the AC adapter component of the charger, something is wrong within the box, and you’ll need to replace the charger. Stop using any charger that becomes too hot or gives off a burning odor for your safety.

Examine your laptop’s charger port. It should fit in firmly when you connect the charger. If it feels loose, jiggle it around a little to see if you can get a good connection.

Also, inspect the port for any debris that could obstruct a secure connection. With a flashlight, inspect the port for any dirt or other debris that could prevent the plug from working correctly.

If there is filth within, clean it thoroughly with a cotton swab or a toothpick. Do not handle fierce with the port’s internals, or you’ll ruin it.In addition, to avoid potential damage to the wire and port, always allow enough slack in your charging cord.

This precautionary measure prevents the charging port from undue wear and tear. Allowing the AC adapter brick to dangle from a table may cause the connector to pull down and potentially damage the connection.

Is It Okay To Keep Your Power Supply Plugged Into Your Laptop Continuously?

Your laptop is at no risk if you leave the power supply plugged in all of the time. Even the cheapest devices have their battery charging circuitry to avoid overcharging.Overcharging batteries can cause them to explode, hence the charging circuitry property.


In conclusion, to test your laptop power supply, you’ll connect the two poles of a multimeter to your laptop AC adapter. 

A multimeter has two probes, positive and negative, indicated by red and black colors, respectively.Insert your multimeter’s red probe into the power supply plug’s end while pressing the black probe on the plug’s barrel.

The multimeter would produce the voltage reading of your laptop power supply. If the voltage reading is close to the rating on the power supply, then the power is good. Otherwise, you’ll have to get a replacement.

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