AC/DC Power adapter

AC/DC power adapter for a laptop

AC/DC power adapter as known as power supply or power brick converts the high voltage AC power from a wall outlet into the low voltage DC power needed for your laptop.

The AC/DC adapter provides power for the laptop and charges the battery. It’s very important to use the right adapter for your laptop.

If you are looking for a new adapter, you should check the following:
1. Your new adapter must have exactly the same plug (adapter tip) as the original one.
2. Your new adapter must output exactly the same voltage as the original one.
3. Polarity on the new adapter’s plug must be the same as on the original one.

You can find the output voltage and amperage on the adapter’s label. As you see on the picture below, my adapter outputs 19V-3.42A.

AC/DC power adapter voltage and amperage

When you buy a new adapter, you can follow this rule:
The output voltage must be the same, the amperage could be the same or higher than on the original power adapter.

For example, if my laptop requires 19v-3.42A adapter, I can safely use 19v-3.95A adapter.

HOW TO TEST OR REPAIR POWER ADAPTERS.

Most newer laptop power adapters are sealed and you cannot repair them. If the adapter is dead, you’ll have to buy a new one.

1. How can you tell if the AC adapter is dead? You can test it with a voltmeter. On the picture below I’m testing a 15V adapter and as you see the output is 15.45V. It’s pretty normal and there is nothing wrong if the output voltage is a little bit higher but if you are getting 0V, the adapter is definitely bad.

Test laptop AC/DC power adapter

2. If you accidentally damaged the adapter plug, you can replace it with a new one. Just make sure the new plug has the same size as the old one. Cut off the old damaged plug and solder a new one.

 

179 Comments

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  1. 179
    Chantelle Says:

    Hi I have a Toshiba Satellite C850 laptop that my dog chewed the crap out of the charger for. I bought a universal charger that was supposed to be for all Toshiba laptops as well as a variety of other makes, but it blew my laptop’s motherboard up twice. Now my year warranty is up and I don’t want to blow it up again, so im not using the universal charger anymore. My friend has a Toshiba Satellite too but it’s a different model. The back of my laptop says it’s 19 volts and 3.42 amps and my friends charger says its output is 19 volts and 6.32 amps. Can I use her charger without risking any damage to my laptop? I already spent 80 dollars on a piece of crap universal charger that blew my laptop up.. I can’t a

  2. 178
    RAJ Says:

    Hello Sir,

    I have the AC adapter is originally 19 volt 3.42 AMP that is dead. I got a old thinkpad charger with 16 volt 4.5 amp . can i use for my laptop

  3. 177
    Chitra Says:

    for my Toshiba Satellite laptop (AC/DC adapter – 19V) can i use 20V adapter(AC/DC)

  4. 176
    frenchmal Says:

    Hi ,

    on my laptop Brand ” Toshiba satellite A200 2BH ”
    the fuse on the motherboard seems to be blown…?
    the ac adaptator is on and work (tested)
    where do i find the main fuse on the motherboard?
    Do you have photo please

    Regards thank before

  5. 175
    julie Says:

    hi mr repair man i am using a 19v 3.42a charger for my toshiba laptop but it damage is it possible to use a 19v 4.74a toshiba or will it damage my computer thank you julie

  6. 174
    Bill Says:

    Charging my Toshiba Satellite laptop has become a problem. Sometimes it takes a charge. Sometimes it doesn’t, for more than a moment or two. Does this likely indicate a fault within the laptop or is the adapter possibly at fault? I’m currently thinking of buying a replacement adapter just to try it out….but maybe adapters either work or don’t work? Thanks!

  7. 173
    Eric Says:

    My Dell inspiron Mini has a 19V, 1.58A adapter s it okay I I use a 20V, 3.25A ac adapter. Will it damage my mobo? Thanks.

  8. 172
    allen Says:

    hello, my previous acer laptop adapter was 19 v. 3.42 a, but it damaged. so could i replace it using universal laptop adapter with 90w, 19v and 4.74? thank you.

  9. 171
    Anun Says:

    M using a IBM R52 laptop which takes the output of 16V,4.5A. My adaptar has got damaged somehow. And my batry is also not working. It gives 0 sec bakup. So it means it works directly. I have a old hp adapter of 18.5V,3.5A. So could I use it with my laptop via a connector??

  10. 170
    CG Says:

    My original HP dv6 AC Adapter is:
    Input: 100-120V~50-60Hz 2.0A
    Output: 18.5V 6.5A

    My replacement AC Adapter is:
    Input: 100-120V~1.8A-0.6A 50/60MHz
    Output: 18.5V 3.5A

    Will my replacement AC Adapter damage my HP dv6 laptop? I’m concerned about the Output be half of the original Output. Thank you for the feedback in advance.

  11. 169
    Repair Man Says:

    @ yve,

    yeah it has the same plug,so theres no issue with the amps,from 4.74 to 6?

    No problem. The laptop will take as much as it needs.

  12. 168
    yve Says:

    yeah it has the same plug,so theres no issue with the amps,from 4.74 to 6?

  13. 167
    Repair Man Says:

    @ yve,

    My toshiba use a 19v 3.74a adapter.It crapped out,I have a 19v 6a adapter,can I use that?

    If your 19V~6A adapter has same plug type you can use it.

  14. 166
    yve Says:

    My toshiba use a 19v 3.74a adapter.It crapped out,I have a 19v 6a adapter,can I use that?

  15. 165
    Repair Man Says:

    @ Tana,

    I am looking at buying a new power adapter for my acer aspire laptop. It is giving me 2 options, the fixed U-tip or the fixed C-tip. What is the difference between the 2

    What is your laptop model number? Acer Aspire ###?

  16. 164
    Tana Says:

    I am looking at buying a new power adapter for my acer aspire laptop. It is giving me 2 options, the fixed U-tip or the fixed C-tip. What is the difference between the 2???

    Thanks

  17. 163
    Repair Man Says:

    @ carlos,

    I need a new charger for my laptop. It is 19v charger. On the other hand, I have some 15v charger from my old toshibas. Is there any way to mod my 15v charger into 19v charger?

    You cannot do that. Laptop AC adapter not repairable and usually they are sealed units. Just buy a new adapter.
    I wouldn’t use the laptop with a 15V adapter. You can damage the motherboard.

  18. 162
    Repair Man Says:

    @ Bashara,

    I have a 19v-3.95A adapter. Can i use 19v-3.42A?

    Most likely the laptop will work with 19v-3.42A. It might take longer to charge the battery but it will work.
    I wouldn’t recommend using it for a long time. It’s better to use the same adapter as the original one.
    Also, do not buy cheap third party and compatible adapters. Buy the original adapter.
    You can buy genuine 19v-3.95A adapter on eBay for about $15-20.

  19. 161
    carlos Says:

    Hello sir, I need a new charger for my laptop. It is 19v charger. On the other hand, I have some 15v charger from my old toshibas. Is there any way to mod my 15v charger into 19v charger?? Its OK if I have to prick my 15V charger apart. (i’ve done that several times). I will greatly appreciate if you send me a copy of your answer to my e-mail. Thank you in advance

  20. 160
    Bashara Says:

    I have a 19v-3.95A adapter. Can i use 19v-3.42A?PLS i need an answer ASAP.tanx

  21. 159
    Repair Man Says:

    @ joey,

    i’m using the huntkey adapter for my hp mini 1000 instead of using the proper hp adapter. my question is the hunt key adapter output 19v. but my battery 11v. it’s got any side effect

    Do not look at the battery voltage.
    The most important is matching your new adapter voltage with the original adapter voltage. The motherboard will convert it into 11V as required by the battery.

  22. 158
    joey Says:

    i’m using the huntkey adapter for my hp mini 1000 instead of using the proper hp adapter. my question is the hunt key adapter output 19v. but my battery 11v. it’s got any side effect. thanks

  23. 157
    Repair Man Says:

    @ Big dog,

    You did not say what would happen if the amperage was lower. For example could you replace an Adapter with an output of 19v 6.32amps with one that produced 19v and 6.3amps?

    Using a 19v~6.3A adapter instead of 19V~6.32A? You should be fine.

  24. 156
    Repair Man Says:

    @ benj,

    I have laptop the AC adapter is origenally 18.5 volts 3.5 aperes is dead… i am using temporarely 18 volts 20 volts amperes, there”s no side effect in laptop?

    Can you switch between 18 volts and 20 volts?
    I really don’t like adapter with multiple voltage output.

  25. 155
    Big dog Says:

    Hi repair man.

    I have been reading through you Q & A’s and you have said that when replacing the adapter the voltage must be the same, however the amperage can be equal to or more than the original adapter.

    You did not say what would happen if the amperage was lower. For example could you replace an Adapter with an output of 19v 6.32amps with one that produced 19v and 6.3amps?

    Or would doing this cause potential damage or problems with the laptop?

    Many thanks

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