Electrical pressure that flows through wires is measured in volts. A good comparison is the force or pressure of water that flows from your water tap. Batteries produce low-voltage electricity -- between 1.5 and 12 volts -- while your home electricity supply produces high-voltage electricity -- 120 volts in the U.S. If you're not sure that your electrical item is drawing the correct voltage, then an accurate and simple method is to check using a voltmeter.
Things You'll Need
- Protective gloves (if checking home electrical voltage)
- Voltmeter (or multimeter)
Put on protective rubber gloves, if you intend to check the voltage draw of your home electricity supply. It's not necessary to wear gloves if you are checking low-voltage electricity from a battery or transformer, as it's not dangerous.
Turn on your voltmeter. Set the voltmeter to the correct voltage range based on the voltage draw you are expecting. For example, if you are checking your home electricity, set it between 100 and 150 volts; if you are checking the voltage draw from the 12-volt transformer, set it at 6 to 15 volts. All batteries and transformers have the voltage on the labels.
Place the prong on the end of the red wire from the voltmeter onto the positive terminal of the battery or transformer labeled "+." If you're checking a transformer, be sure it's plugged in and turned on. If you're checking your home electricity voltage, you need to place the prong onto the terminal where a black, red or orange wire is connected. You can find this by removing the plug cover using a small screwdriver.
Place the prong on the end of the black wire from the voltmeter onto the negative battery or transformer terminal labeled "-." If you're checking your home electricity voltage, you need to place the prong on the terminal where a white wire is connected.
Read the voltmeter display. This tells you the voltage draw of the electricity supply. Remove the prongs from the terminals or plug connector. If you checked your home voltage, replace the plug cover.
Tips & Warnings
- You can use a multimeter instead of a voltmeter. Just be sure you set the meter to read voltage before proceeding.
- Photo Credit Stockbyte/Stockbyte/Getty Images
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