By the way, an easy way to determine the correct polarity is with a 1.5v LED.

The red LED can also be used to check if you have the correct polarity.

When operated on DC, they would only work if the plug was inserted with the correct polarity.

Although Apple smart covers, of course, are correct polarity.

In most instrument devices it is very important to connect them with correct polarity for correct power or current direction measurement.

Supercapacitors are polarized and must operate with the correct polarity.

Supercapacitors are polarized, and may be operated only with the correct polarity.

Transposing the wires to the correct terminals will set the correct polarity.

McNeile maintained that the cast-iron body of a porcelain tub confused the spine's natural attempts to return to its correct magnetic polarity.

Automatic optical inspection for presence of components, correct polarity, and letters or numbers on ICs.