Mains Power Multi Voltage, Adapter 'plus or Minus' Quandry?

  Graphicool1 13:39 14 Aug 2011

Hi this is a non PC question. I have a 'Mains Power Transformer'.

It's settings are...

Input: 220-240v AC 50Hz

Output: 3v / 4.5v / 6v / 7.5v / 9v / 12v

DC 300mA

It has 5 different connectors, for different appliances.

Plus - and hereby lies my dilemma - 2 sliders. Other than one slider being a shade longer than the other, they are both the same. Each has a 'Minus' at one end and a 'Plus' at the other. I can use either slider, but whichever one I choose means I can't use the other? This is not my field of expertise and I don't want to make a possible costly mistake.

So, my question is: Do I use the long or short slider and where do I position the sliding marker. I can have it on a Minus or Plus, or postion it anywhere between.

  robin_x 13:51 14 Aug 2011

I bet the long one is lower to higher (3V to 12V) and the short is Polarity.

Can you measure with a multimeter? If you get a +x.xx reading with Black test lead on outer and red on inner, you are on Centre Positive. Your equipment should match.

Voltage may be higher than expected on 'no-load'. It drops to correct value when you connect.

Google for a .pdf User Guide. The label will give you a model number.

Or post an photo via Imageshack or similar.

  Fruit Bat /\0/\ 13:56 14 Aug 2011

Look very carefully at the slider markings are they sowing a symbol for the inner and outer pins of the jack plug?

I think they allow you to set whether innner plug is + and outer - and vicer versa

How you set depends on what you are powering for instance my laptop adaptor is = on inner pin.

  Graphicool1 14:24 14 Aug 2011

Hi robinofloxley

"Can you measure with a multimeter?"

I have one, but unfotunately I can't put my hands on it at the moment, as we are between moves and most of my stuff is in storage. Further more, I don't know anyone who lives anywhere near me, who might have one. Perhaps I'll have a go with 'Imageshack' and a pic or two...

*Hi Fruit Bat /\0/*

"are they showing a symbol for the inner and outer pins of the jack plug?"

No, there is nothing written or any diagram referring the sliders to the pins.

  Graphicool1 14:56 14 Aug 2011

Ok guys

I've just had another route around in my bag of leads and found another multi adapter. This is almost the same as the other one, but only has one slider. This halves my chance of getting it wrong. Theres a sticker on this one, which seems to clear up what the slider is for, it reads...

"Always read the product instructions manual to determine the correct polarity and voltage settings required"

well as I need 9v I've set it to that and because the only other thing that can be changed is the slider; then by a process of elimination, that must be the polarity setting.

My problem here is, I don't know what the polarity setting should be, or even what it means?

So, I have a '-' a gap '+' below this is 10/92

Everything else is the same as on the other adapter, even the make. Which is 'TARNPOINT' made in CHINA

  Nontek 15:21 14 Aug 2011

Different items which may need the use of the adapter, can come with either polarity. Most have a +(Pos) polarity to the Centre pin, with - (negative) being the Outer pole. Though as I said, some may be the other way round, with the Inner pin being Negative, and Outer Positive. Most items needing such an adapter are clearly marked as to which is Pos and which is Neg.

  Graphicool1 15:54 14 Aug 2011

Hi Nontek

I've found the instruction that came with the item, lucky I did. Because although I was told it was 9v, it is in fact 11-15v. As my adapters highest setting is 12v, then that's what I'm setting it to. As for the polarity setting, next to where you plug in the adapter it shows...

+ ____o____ -

The 'o' represents a dot in a circle at centre point. Would you think, as I do that this means the slider should be set in the centre of the line?

The item 'Hardware' in question is a 'TASCAM Mini Studio PORTA 03mkII' or in other words a music/sound mixing studio.

  Nontek 16:00 14 Aug 2011

Unusual markings, but I would say that this shows Center polarity as Positive + (A dot in a circles means Center Pin)

  Graphicool1 16:12 14 Aug 2011

So does that mean I should set the slider to '+'

  Graphicool1 16:15 14 Aug 2011

If I were to set it to the wrong polarity, what would actually happen. Would it just not work or worse?

  Nontek 16:19 14 Aug 2011

What is it that you wish to use the adapter on? For instance if it was to run a small motor, wrong polarity would just cause it to run backwards instead of forwards, and could then be reversed without problems.

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