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Activity #3: Measuring AC Voltage


Multimeters are also important tools for measuring AC. It is important to be very careful when measuring AC. If you take precautions, you will be safe.


DVM 810 Set your meter to 500 volts AC

AC IS DANGEROUS AND CAN KILL. Always be very safe and careful when handling AC voltages and current. Wear rubber shoes and remove metal jewelry that could accidentally contact electrical materials. Proceed at your own risk.


  1. Take an extension cord and carefully plug it into a wall socket.
  2. Set your multimeter to the AC setting of 500 volts or more. You should always start with your AC setting as high as it will go, which is 500 volts on many multimeters.
  3. Carefully, being sure to isolate your hands and fingers from the metal at the tip of your multimeter probes, slip the probes into an extension cord socket as below.

    Carefully insert the probe tips into the two long flat areas. You may have to shift them around a bit to make a proper connection

  5. How much electrical pressure does the AC setting on your meter read? ___________________
  6. Carefully remove the multimeter probe tips.
  7. Now, turn the multimeter setting to the AC 200 volts and carefully read the voltage again. (if you are in a country with 220 volts AC 50 HZ then leave your meter on 500 volts AC for this measure.
  8. What is the electrical pressure reading? ____________

Notice how it is more accurate than the 500 setting on the multimeter?

Why do you think this is the case?______________________________________________________