Back To Basics: Voltage Measurement

How is a voltmeter usually connected to a circuit under test?

Question B-005-013-001 - From The Canadian Basic Question Bank

A handy thing to know, particularly as basic digital multimeters (DMMs) are now very inexpensive, usually less than $10., and can be useful for many things around the home like checking the condition of batteries.

The two types of voltmeter you may encounter are digital and analog.  Analog meters are recognizable by their printed scale and a moving needle. 

Voltage is always measured in parallel with a device, current in series. If you recall Ohm’s Law in your (Canadian) Basic Qualification, you will remember series, parallel and series-parallel circuits. If not, check this link:  http://www.physicsclassroom.com/class/circuits/Lesson-4/Two-Types-of-Connections

On the meter, first set the knob to a voltage range greater than the expected voltage. If you don’t know what to expect, set it to the highest range.  DC Voltage range has a V- with a straight line next to it, AC generally a V~ with a wavy line. For example, 2V measures voltages up to 2 volts, and 20V measures voltages up to 20 volts. In our circuit the meter is hooked up in parallel to measure the voltage of the component under test.

The correct answer therefore: In parallel with the circuit.

~ John VE7TI