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  1. Member pchan's Avatar
    Join Date: Mar 2003
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    Hi All,

    Can I use a 19V 4.74A power supply on a Acer 23inch LCD monitor that need 19V 2.1A input ?

    Thanks in advance.
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  2. Depends whether the original and the new power supply are regulated or not and if they both are the same type output, AC or DC.

    If the 2.1A unit is just a transformer (would be heavy, at that output it would weigh over a pound), then the answer is no.

    If it's a switching supply (relatively light, less than 1/2 a pound), then yes. It would also say the output is regulated on the sticker.
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  3. Member pchan's Avatar
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    Thanks. The load should be light since it's a LCD monitor.
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    If doesn't hurt anything to use an adapter with more current capability. What current it'll draw is a function of ohm's law, ie. incidental really to the process of supplying volts. If it had half the amps that would be a problem.

    What does matter, along with whether it's actually a DC supply or not as mentioned, is the polarity of the connector. Usually the outer connector is ground but sometimes it's positive, and that's not really unusual.
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  5. Member pchan's Avatar
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    Sorry. When it comes to expert, all the fine details are very important.

    It's a Delta laptop power supply that takes in 110-240V AC and output 19V DC 4.74A.
    Strangely enough, the output socket fits exactly into the LCD monitor power input.
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  6. Member turk690's Avatar
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    Location: ON, Canada
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    oh use the PSU already and tell us what happened
    Tablet? No, I don't have a tablet. I have a life.
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  7. was that a siren?
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  8. Originally Posted by Hoser Rob View Post
    If doesn't hurt anything to use an adapter with more current capability. What current it'll draw is a function of ohm's law, ie. incidental really to the process of supplying volts. If it had half the amps that would be a problem.

    What does matter, along with whether it's actually a DC supply or not as mentioned, is the polarity of the connector. Usually the outer connector is ground but sometimes it's positive, and that's not really unusual.
    Good of you to mention the plug polarity, but you're more or less correct on the supply capacity.If you're talking about a regulated power supply, yes it will always output the same voltage (within tolerance) as long as the current draw from the load is below its rating (always in Watt).

    On the other hand, a simple wall wart that only uses a transformer and diodes to convert AC to DC will have a varying voltage in relation to the current being drawn and most of the time the rating is in Volt-Amp. You can easily verify this with a voltmeter; they never read the voltage on the label, it's not unusal for a 12 V brick to read 18-20 V on a meter.

    A quick example, the current (I) being drawn from the power supply is that which is required by the load (R), R and I are physically set by the electronics of the device. If the device required 12 Volt and 0.5 Amp to operate with an original 7 VA supply and you swap the power supply with one that has 14 VA capacity, the device's R and I requirements have not changed, but pulling 0.5 A from that supply might present 16 V to the device (it's not a perfectly linear relation).

    A higher voltage is not that much of a bad thing in itself, the problem comes from the device's power dissipation capability. Easy way to visualize this, go in your PC's BIOS, only raise the CPU voltage by 10% and watch the temperature rise.
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  9. Originally Posted by pchan View Post
    Sorry. When it comes to expert, all the fine details are very important.

    It's a Delta laptop power supply that takes in 110-240V AC and output 19V DC 4.74A.
    Strangely enough, the output socket fits exactly into the LCD monitor power input.
    Don't you see regulated or switching on the label? I'm 95% sure the laptop supply is regulated and will work just fine, but certainty would be nice. Like Hoser Rob said, watch the plug polarity (also on the label).
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  10. Member turk690's Avatar
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    Originally Posted by pchan View Post
    It's a Delta laptop power supply that takes in 110-240V AC and output 19V DC 4.74A.
    Strangely enough, the output socket fits exactly into the LCD monitor power input.
    It's a typical switch-mode PSU brick. Use it FWIW.
    Tablet? No, I don't have a tablet. I have a life.
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  11. Member pchan's Avatar
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    Thanks for all the replies. It works.
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  12. Member turk690's Avatar
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    Originally Posted by pchan View Post
    Thanks for all the replies. It works.
    Good.

    Originally Posted by Constant Gardener View Post
    was that a siren?
    that was my cat
    Tablet? No, I don't have a tablet. I have a life.
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  13. Member pchan's Avatar
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    No siren.

    Years ago, I opened up a Sony TV because one of AV connections was bad. I thought it was OK since it was unplugged. That suckers was fully charged and it gave me a jolt. From that on, I am extra careful with electrical stuffs.
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