Need to keep voltage constant but drop current by .3 A, please help...HOW TO? It is coming from a power supply

Question

I have a power supply whose outupt is 20V and 6.3 A.

The power supply has 2 positive cables and two ground cables coming out from it.

I need an output with the same cable design but that has 20V and 6A rather than 6.3 A.

What should I connect and where?

Please make it simple for me, thank you!!!

I am using this to power a computer which has a DC power supply.

I know that i have to get it down to 6A because the makers of this power supply sell two different models, one with 20V and 6A and one with 20V and 6.3 A and the one included for my computer is a 6.3A so I assume they wouldn't make two totally different power bricks if they could be used interchangably.

Can you just tell me if i should put a resistor in parallel or something like that to get it down?

Thanks

Answer 1

Just use the 20V at 6.3A directly. You will be just fine. I have been in electronics for more than 20 years, and I would not give it a second thought.

If you are concerned in spite of this, feel free to add a 6A slow-blow fuse in series with the positive wire. If your computer tries to draw over it's rated current, the fuse will blow and stop it.

Answer 2

The current rating on a power supply does not mean that it is constantly delivering that amount of current. It is the maximum design limit for the power source, at the designated voltage. Most power supplies have a regulator to control the voltage, and in the case of computer power supplies this is usually an above average voltage control. That is....voltage is more important to transistor circuits.

A good example of a device that requires a fixed voltage, but varying current is a light bulb. A 100 watt bulb draws more current than a 50 watt bulb, but they both run on the same voltage.

So as long as your equipment doesn't need more than 6.3 amps, as long as you have the voltage required it will work fine.

Answer 3

How about this for simple....

Here goes....

Do nothing.

Power supplies are rated for voltage and MAX DELIVERABLE amperage. Your computer will draw the exact amount of amperage it needs. You just have to make sure that your computer does not draw MORE amps or a DIFFERENT voltage than the power supply is rated for.

For example, if your computer only needs 3 amps at 20V to run, you could install a 20V, 100 amp power supply and that power supply would only put out 3 amps.

All you have to do is pick the correct power supply with the correct voltages and connectors. The amps will take care of itself.

Answer 4

The 6.3A is just the maximum the power supply will put out. It's the thing you're powering that determines how much current is being delivered. As long as the voltage is right you can use a 20V milliom amp power supply and you'll be fine. The device you're running will only draw as much as it needs.

Answer 5

Get a new power supply. If you know of one that you are sure will work go get it.

I've just read your clarification - contact the manufacturers and ask _them_ whether it's o.k. to use either supply and if not why not.

The second simplest way of solving your problem is to completely redesign whatever you are connecting to it to tolerate a 6.3 A condition if it should ever draw that much.

If you really can't do that then the next simplest aproach is to get the circuit diagrams for your regulated power supply and work out which component changes you need to make to limit o/p current to 6A or less, open the box, make the changes, test it thoroughly, document the changes, kiss your warranty goodbye.

Best of Luck - Mike

Answer 6

I agree with Scott. Power Supply specifications provide the voltage at the which the supply is designed to operate and the "maximum" current it will provide. It will provide whatever current the "load" requires up to it's designed maximum output.

Answer 7

What is your application? You should be able to use it as is.