# 9 + 9 = 18 ?

• posted

I Know that this is a dumb question but, I am curious anyway.

Lets just say that I need an 18 volt DC power source and that the source has to come from one of those transformers? that plug into the wall and change AC to DC.

What if I only have two of those transformer devices that are 9 Volts DC each.

Now, If I cut the insulation off of the ends of both of those transformers, take the two wire ends from each and twist the 4 ends together to make two again, plug them in, will THAT make me the 18 volts that I need?

9 + 9 makes 18 doesn't it?

Thank You Brenda

• posted

no, that will be 9 volts only. you cann cut the connectors of and wire the negative of on 9v adapter to the positve of the other adapter. remember you have to "add" the voltages

• posted

goes, if u use them in series

yes, but ONLY THIS WAY:

source#1 +9V --------------------------------- +18V out -9V -----+ | | (connect the wires) source#2 +9V -----+ -9V --------------------------------- GROUND

HTH fritz

• posted

what i think you are talking about is paralel connection. this would double the power but woudlnt increse the voltage. you need to make a serial conection. each power adapter has a positive and negative wire. you need to connect positive wire of one adapter to negative wire of the other.the voltage betven two remaining(unconected) wires will be 18.

• posted

You need to connect them together in series not paralel.....but first ...

If the mains adaptor has an earth pin you need to check that neither of the output wires is connected to the earth pin.

If it is connected then you will damage one of the power supplies.

• posted

-I Know that this is a dumb question but, I am curious anyway.

-

-Lets just say that I need an 18 volt DC power source and that the source

-has to come from one of those transformers?

A bit more than just a transformer.

- that plug into the wall and

-change AC to DC.

Commonly known as a "wall wart"

-

-What if I only have two of those transformer devices that are 9 Volts

-DC each.

The you probably have a problem.

-

-Now, If I cut the insulation off of the ends of both of those

-transformers, take the two wire ends from each and twist the 4 ends

-together to make two again, plug them in, will THAT make me the 18 volts

-that I need?

No. It'll most likely blow one or the other of the wall warts depending on how you wired it.

Your best bet is to get the correct supply for what you need. 18V is commonly used by laptops so finding such a supply shouldn't be difficult.

BAJ

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