Charger polarity - how to tell?

netrate

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I have recently acquired a charger , but all of the information is in Chinese and there are no markings to indicate which side in + or -. I know that trying to charge something with the wrong polarity is a no-no, so how can I figure out the polarity from just the charger? Do I need to take it apart? Is there a "tell"?
 
What battery connection is on the charger? Post a pic.

That said.. With a voltmeter and both probes connected... if the red probe is on the positive conductor it will read the voltage as a positive number with no preface
If the red probe is on the Negative conductor it will read a number with the - preface

 
This hint goes back to the dark ages at least. Most 2 strand corded wire will have some sort of "tracer" on one side, the other will not have it. Could be a tiny rib or 2 molded in, could be a white stripe. In either case, that will be your positive lead.

Voltmeter/VOM the way better plan though.....
 
This hint goes back to the dark ages at least. Most 2 strand corded wire will have some sort of "tracer" on one side, the other will not have it. Could be a tiny rib or 2 molded in, could be a white stripe. In either case, that will be your positive lead.

Voltmeter/VOM the way better plan though.....
I've never seen that used with DC as a standard. It is with AC as no matter the cable type the Neutral conductor must be identified.
That said in cases like this the wire is typically 2 conductor with and outer clean round jacket.
 
I've never seen that used with DC as a standard. It is with AC as no matter the cable type the Neutral conductor must be identified.
That said in cases like this the wire is typically 2 conductor with and outer clean round jacket.
Some of us have seen it, otherwise I wouldn't have said anything? Especially on chargers/wall blisters. Agree though, "lamp cord" is more frequently seen with AC.
 
Some of us have seen it, otherwise I wouldn't have said anything? Especially on chargers/wall blisters. Agree though, "lamp cord" is more frequently seen with AC.
I'm not saying that you haven't seen it... I'm saying that it is not a standard by any means... so hence it can't be relied upon.
If I came across a charger built with lamp cord... For sure I would break out the meter
 
Thank you for the responses. I took some pictures which might help.
 

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Thank you for the responses. I took some pictures which might help.
That's an AC cable used in a DC application which is perfectly fine for low current situations as this.
But you will need a voltmeter to determine polarity.
 
Yeah and I want to be absolutely sure about it because if not, I believe it will burn out the charger or damage the batteries?
 
A bit confused. Does the other end plug into an AC outlet? Does that end plug into a charging brick that has a cable out that is DC? If yes to both, it will all go together only one way.

It looks like a standard computer power cable.
 
Yes the photo was an example of a ac/brick/dc charger because ROAMERS asked about it -- it is an example of just one charger. It is for sale at amazon.
The one I have, as I have stated in the original post, does not have any markings (see pics)
 
You use a mating connector and connect the resistor to the pins with alligator clip leads. When the voltage doesn't have a minus in front of it, the pin connected to the red meter lead is the plus.
A simple cheap multimeter may be more user-friendly. Not many here are up to speed using resistors and components when a multimeter is so much easier. Thoughts? If polarity has reversed a multimeter will flag a - minus sign. Easy peasy! No?
 
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