How to Determine the Positive and Negative Poles of a Speaker
2 Answers
When the speaker cone retracts inward, the terminal connected to the positive pole of the battery is the negative pole of the speaker, and vice versa. Set the multimeter to the ohm range, then touch the two terminals of the speaker with the probes. The speaker will move slightly when contacted, and pushing forward indicates the standard positive and negative poles. Generally, for audio output wires, the wires for the same speaker will be of the same color group. The positive wire will be solid-colored, while the negative wire will have thin black lines or dashed lines.
I've been repairing cars for years, and determining the positive and negative terminals of a horn is actually quite straightforward. The horn has two wires: the positive is the power supply wire, and the negative is the ground wire connected to the car body. If you want to be precise, use a multimeter: place the black probe on a metal part of the car body as the ground, and touch the red probe to the wire end. If it shows a voltage (usually around 12 volts), that's the positive; if it shows nothing, it's the negative. No professional tools? Try a small bulb tester: connect it to the power source, and the wire that lights up the bulb is the positive. Or use trial and error: connect directly to the battery—if the horn sounds, the connection is correct; if not, swap the wires and try again. Remember to turn off the engine and disconnect the power before working to avoid short circuits or fires. This is important because reversing the polarity can burn out the horn's internal coil, leading to weak sound or no sound at all. On older cars, the wire ends may be faded, so beginners should start with basic tests.
