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A Question Of Voltages

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Excuse the ignorance:

When I have a bust ac/dc adaptor how do I know if it's safe to use an alternate one? I know the voltage must be the same, but sometimes when I've searched the big box of adaptors and found one with the same voltage, the size of the connector is different. Why is this?

If the voltage is the same and the connector fits is it safe to use? Do I need to check anything else?

p.s. I just want to know a quick and dirty rule to check so if possible please don't

mention "Ohms Law", "electron", "capacitor" or anything saucy like that,

unless it directly relates to my query. I have no interest in it and would rather

bang rusty nails into my head and rub sea salt onto the weeping wounds than know,

unless I absoultely need to.

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Excuse the ignorance:

When I have a bust ac/dc adaptor how do I know if it's safe to use an alternate one? I know the voltage must be the same, but sometimes when I've searched the big box of adaptors and found one with the same voltage, the size of the connector is different. Why is this?

If the voltage is the same and the connector fits is it safe to use? Do I need to check anything else?

p.s. I just want to know a quick and dirty rule to check so if possible please don't

mention "Ohms Law", "electron", "capacitor" or anything saucy like that,

unless it directly relates to my query. I have no interest in it and would rather

bang rusty nails into my head and rub sea salt onto the weeping wounds than know,

unless I absoultely need to.

Keep the voltages within 10% of each other e.g. a 12V supply should be ok for an 11V laptop. The critical thing is current rating. Look for a rating on the device in Amps (A) or milli-Amps (mA), and compare it to the rating on the supply. The supply rating should be greater than the device requirements, with at least a 10% margin.

No rusty nails or sea salt required, but you might burn your fingers putting out the flames if you ignore Mr Ohm!

p.s. there are several industry standard connectors, but several manufacturers will use a non-standard interface to force you to buy their replacement parts.

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Excuse the ignorance:

When I have a bust ac/dc adaptor how do I know if it's safe to use an alternate one? I know the voltage must be the same, but sometimes when I've searched the big box of adaptors and found one with the same voltage, the size of the connector is different. Why is this?

If the voltage is the same and the connector fits is it safe to use? Do I need to check anything else?

p.s. I just want to know a quick and dirty rule to check so if possible please don't

mention "Ohms Law", "electron", "capacitor" or anything saucy like that,

unless it directly relates to my query. I have no interest in it and would rather

bang rusty nails into my head and rub sea salt onto the weeping wounds than know,

unless I absoultely need to.

Further to what ATW said above, also check the polarity of the connector is the same on the replacement transformer.

i.e. if the core is positive on the old transformer, it must be the same on the new transformer. There's normally a little diagram on the transformer showing the polarity.

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Connector needs to be the same.

Polarity of the connector needs to be the same (DC).

AC / DC Output type needs to be the same.

Voltage of output needs to be the same (ish) as outlined above.

Current rating of the new adapter needs to be at least the current output of the orignal adapater so that it can supply enough juice without burning up - and some will if you overload them. So will some even if you don't. As far as you can never leave these things plugged in.

Get a cheap multimeter from Maplin or CPC. The cheapest will do the job and be useful for other testing.

Get a multi-adapater - variable voltage, variable connectors - goor for power up different stuff infrequently where the power supply is lost or broken - but again cheap amp output.

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Further to what ATW said above, also check the polarity of the connector is the same on the replacement transformer.

scotty.jpg

Aye, whitever ye do, dinnae reverse the polarity, laddie.

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scotty.jpg

Aye, whitever ye do, dinnae reverse the polarity, laddie.

Just don't reverse the polarity of the neutron flow.

baker.jpg

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Guest DissipatedYouthIsValuable

Current limiting is as important to charging batteries as voltage limiting.

It depends on the type of battery as to which kind of charge profile is optimum.

Lead-acid batteries can take quite a lot of abuse, as can Ni-Cads.

Lithium based batteries need a bit more of a gentle approach.

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Unbelievable! A technical question on an Internet Forum answered in full, on time,

correctly (as far as I can tell) and within budget! Well done! I fully predict 10 people

who come across this thread in years to come will die of total shock that it hasn't been

answered with one pedantic reply and nothing else. Athirdway, Huw, Onlyme, Dissapatedyouthguy

you leave with 5 star ratings from me.

Scunnered & Slumlord, you leave with nothing.

Goodbye!

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Unbelievable! A technical question on an Internet Forum answered in full, on time,

correctly (as far as I can tell) and within budget! Well done! I fully predict 10 people

who come across this thread in years to come will die of total shock that it hasn't been

answered with one pedantic reply and nothing else. Athirdway, Huw, Onlyme, Dissapatedyouthguy

you leave with 5 star ratings from me.

Scunnered & Slumlord, you leave with nothing.

Goodbye!

.. not even a point for entertainment value?

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scotty.jpg

Aye, whitever ye do, dinnae reverse the polarity, laddie.

I did, and it cost the lab quite a lot! :huh:

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Guest X-QUORK

Unbelievable! A technical question on an Internet Forum answered in full, on time,

correctly (as far as I can tell) and within budget! Well done! I fully predict 10 people

who come across this thread in years to come will die of total shock that it hasn't been

answered with one pedantic reply and nothing else. Athirdway, Huw, Onlyme, Dissapatedyouthguy

you leave with 5 star ratings from me.

Scunnered & Slumlord, you leave with nothing.

Goodbye!

The Scotty and Dr Who pics saved your thread from entering the Most Boring Thread thread Hall Of Shame.

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The Scotty and Dr Who pics saved your thread from entering the Most Boring Thread thread Hall Of Shame.

I was hoping I was making a valid point, with pictures for added emphasis. It really is important not to reverse the polarity. Never mind though.

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The Scotty and Dr Who pics saved your thread from entering the Most Boring Thread thread Hall Of Shame.

:huh:

My mate wasn't bored when he returned from holiday to find his living room totally burnt out - luckily the door was shut and the fire didn't spread through the rest of his house. There was still smoke damage to clothes in upstairs bedrooms (the clothes were inside draws). Took months for repairs.

Cause - one crappy walwart power adapter - it was the right one too.

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You can get an "almost" universal adapter from Maplin or similar. Selectable voltages, and reversible interchangeable tips, so you can get the right voltage in the right way through the correct size hole!

If you are looking for a laptop one, these are a little more expensive, but multiple voltage ones are available, depending what yer laptop needs!

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  • 140 Brexit, House prices and Summer 2020

    1. 1. Including the effects Brexit, where do you think average UK house prices will be relative to now in June 2020?


      • down 5% +
      • down 2.5%
      • Even
      • up 2.5%
      • up 5%



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