Identifying Plus & Minus on 12V Power Supply with Torn Terminals Using a Meter

Hello, if you have a digital meter and it will show you, for example, 12.0V, then you have (+) on the red wire, and if -12.0V (a dash before the value), it will be (-) on the red wire.

I meant the wires to the meter, you can still check the electrolytic capacitor at the output of the power supply will be marked (-) on it, check which wire is connected to it.

Buddy, lead the wires outside the power supply and bring them to
the cut potato. There will be an environment on the positive pole / + /
the tips on the potato are red, the negative pole / - / will be
the potato was dyed blue. Note!. Be careful only
low voltage on the secondary side of your power supply You can check this.

dadurec wrote:

so that both wires in the power supply are black, including 1 with a white stripe along the length. Could you please explain to me how for "total crowd" ?? ;] because I don't know much about electronics.

The statement of my colleague is very vague. I assume the wire with the white stripe is plugged into the (+) jack. Black - to the (-) slot. You connect the meter. On digital - the previous speaker has already explained to you. On analog - if the (+) from the power supply is on the (+) of the meter, you will measure the voltage. If the (-) of the power supply is on the (+) meter, the pointer will move to the left. If the operation of the meter scares you, take a clear, clear photo and post it on the forum (according to the rules!).

I know the golden shovel is waiting, but this is the highest positioned answer in google I will skip having an ammeter or even any receiver compatible with the power supply specification, let's assume that we do not know which cable is plus and which is minus, and we are total laymen in the world of electricity. There are 2 simple methods for this:

1. Electrolysis: Put 2 cables into slightly salted water, turn on the electricity, from the one where bubbles will be emitted is a minus, if nothing appears on any of them, wrap the cables around a screw or something metal to increase the surface and similarly - bubbles = minus, none = plus.

2. Potato: Cut a potato in half, stick the cables into the potato, turn on, after a few minutes there will be a blue coating on the minus side, and red on the plus side.

I do not need to explain so as not to connect the wires, not to use high voltage current, the intensity is not of particular importance because the receiver will not take more than it needs greetings

The theme and level are suitable for the HydePark department . The author has a meter and you advise him to measure the polarity with potatoes and electrolysis. Just advise what to solder the plug to these wires without a soldering iron, there will be a set.

krakarak wrote:

The theme and level are suitable for the HydePark department

Not even there, but straight to the Trash. I do not believe that in Inowrocław the author would not find someone who can use a multimeter. Such an inquiry on Elektroda should immediately land in the Trash.

Explanation from Lajkonik for Lajkonik?
Assumptions: I have a meter, but I still don't know what or how. ?
I took a battery (it has polarity markings) and connected the battery: I know where the plus and minus are (from the battery). I also know what the meter shows. I connect the meter to the tested voltage source, just like a battery. The meter indication as for the battery (i.e. only + or -) means that the cables are like in the battery, and the opposite sign - the opposite.
By the way, you will also deal with the markings on the meter.

smola76 wrote:

Explanation from Lajkonik for Lajkonik?
Assumptions: I have a meter, but I still don't know what or how. ?
I took a battery (it has polarity markings) and connected the battery: I know where the plus and minus are (from the battery). I also know what the meter shows. I connect the meter to the tested voltage source, just like a battery. The meter indication as for the battery (i.e. only + or -) means that the cables are like in the battery, and the opposite sign - the opposite.
By the way, you will also deal with the markings on the meter.

And if, when I connect the battery, one side and the other and the meter shows me the same thing every time? What am I doing wrong??

A minus should appear (when polarity reversal) before indicating the absolute value in V.

Hmmm,
you do not measure the voltage but a different value available on the multimeter? The voltage is usually marked with V. A R6 battery (finger) should give results in the vicinity of + or - 1.5V (depending on the state of discharge).
Maybe you are connecting something wrong when the meter has more than two sockets.

harnas2 wrote:

And if how I connect the battery one page and the other and every time the meter shows me the same ?? What am I doing wrong??

What are you doing wrong You're having a lot of fun because it's just plain clown without panache.

He makes a joke out of you and you write philosophical essays without reading and thinking ...

I can't comment because I'm not an expert. Recent statements here on the forum negate the point of asking about such grounds. And the most important thing is to start doing something and do it well. Now via Google I found this discussion because I have an old drill/driver from 18 years ago and I bought a battery from a modern Li-ion screwdriver, but there is no plus and minus marked on it. I'm not sure if the connection will be like in the other one, or maybe vice versa. This is where I looked. In other cases, it is also important, when the cables coming out of the battery are not marked, electronics here. Then I connect a battery with marked poles to the motor and look in which direction the rotor turns, and then I connect a battery without markings and also look in which direction the rotor turns. If the same, then the wires set have the same poles as on the known battery. It is the answers, reasonable, simple to such questions, that are most important for those who start doing something.

123dawid13 wrote:

and then I connect a battery with marked poles to the motor and look in which direction the rotor turns, and then I connect a battery without markings and also look in which direction the rotor turns.

And how can you be sure which direction the motor should rotate at a given polarity of the power supply?