Positive negative polarity - Black & Decker Drills

https://www.youtube.com/watch?v=_yTnfRS9B04

So, for gasless MIG welding polarity (when using flux core wire), your MIG welding polarity settings should be set to direct current electrode negative (or DCEN). With DCEN, the negative terminal inside your machine is hooked up to your electrode (your MIG gun) while the positive terminal is hooked up to your ground.

https://makemoneywelding.com/how-to-set-your-mig-welding-polarity-settings/

Most battery powered devices will not operate with the battery connected backwards (Negative to Positive). So the main battery of a car needs to be connected with the correct polarity (Positive to Positive and Negative to Negative) Then all the subsystem componets, like the radio and screen, will also function.

Bottom line is yes, but how the charger connects must be compatible.
If it's a wired charger, connect the charger power wires with proper polarity. Positive to positive, negative to negative.
If the charger is a cigar lighter type, then make, build, or squire a reversed polarity jumper. A male cigar lighter jack with wires output and a female cigar jack on the end of the wires where polarity is crossed.
Please be more specific for a better short answer.

there is no polarity in ac current as ac means alternating current and that means alternating between positive to negative back to positive back to negative and so on
only dc ( direct current ) and the center pin of the plug is designated as the positive pole has polarity, the outer case being the negative
OR Are you asking the voltage of the ac adapter and the voltage of the dc output side of the adapter

RED IS USUALLY POSITIVE
RED-WHITE IS MORE THAN LIKELY NEGATIVE
TO CHECK SPEAKER POLARITY:
1. HOOK LEADS UP AS I DESCRIBED
2.TAKE A AAA,AA,C,OR D BATTERY
3.CONNECT POSITIVE SIDE TO POS ON BATTERY...NEGATIVE TO NEG END......
4. IF SPEAKER "CONE" PUFFS OUTWARD..POLARITY IS CORRECT. IF IT PULLS INWARD..POLARITY IS REVERSED

Computers always use DC voltage. Computer speakers receive DC voltage from the computer.
DC voltage has a Positive and Negative polarity.

In the power jack of the speaker, the Center pin is the Positive connection. The outer shell is the Negative connection.

Center hole of the DC adapter plug - Positive.
Outer shell of the DC adapter plug - Negative

Voltage 5 Volts DC.

In case you need it,

http://support.dell.com/support/edocs/dta/acs5/

Here is how you might check the polarity of a 7.5 volt DC replacement adapter:

Put the 5 batteries into the unit and verify operation. NOW using a DC voltmeter measure the voltage from battery negative and meter negative connected and meter positive to the pin on the power jack. IF you see 7.5 volts positive, then the pin is the positive lead for the adapter.

If you see zero, then continue testing.

With the 5 batteries inserted, connect the positive meter lead to the positive of the stack of batteries. Now touch the negative meter lead to the pin.
If there is 7.5 volts there, then the pin is the negative lead for the adapter.

READ THESE INSTRUCTIONS CAREFULLY.

USUALLY the jack has a contact that disconnects the batteery when the plug with sleeve is inserted.. We are testing the jack without inserting a plug here so the plug should HAVE THE BATTERY VOLTAGE with correct polarity on the pin.

if its color coded,,red is positive and black negative,,,if not hook one up and watch the speaker while playin music,,, if its moving in and out its correct,,if not wrong

If the monitor does not have a symbol (similar to the letter 'C' with a dot in the middle), the cheapest digital multimeter can be used on the 'diode' or 'continuity' setting to check the input.
If the meter reads between 600 and 900, you are measuring the forward voltage drop of a protective diode.  Any other reading will mean that the positive probe of the meter is on the positive part of the connector.     i.e. If you are placing the positive meter lead on the center pin and the negative on the shell and it reads 600-900, then the power supply needs to have the negative applied to the center pin and the positive on the shell. If the negative lead is held on the center pin and the positive on the shell and the reading is 600-900 then the center pin is the positive input and the shell the negative.
The readings shown above mean that you are measuring the forward voltage drop of a diode meant to protect the unit against improper polarization and it will probably either die or ruin the adaptor if misapplying the polarity.
You can buy such a meter at electronics or auto parts stores for under $20 US.

Center pin is positive, and um Zap! Cheers!