How to Read Ohms with an Analog Multimeter
When you need to know some information about an electrical device, an analog multimeter is a great tool to use. Taking readings about the different aspects of electrical devices is important in order to ensure there are no problems within the electrical system. With the analog multimeter, you can take readings on voltage, AC current, DC current and ohms. Even in today's super-digital world, there is still room for some analog equipment.
Step 1 - Become Familiar with the Analog Multimeter
The analog multimeter contains many different dials, switches and numbers that can be confusing if you are not used to reading them. Look over your manual carefully and make sure you understand the basics. You read the analog multimeter by looking at the position of the needle.
Step 2 - Connect the Lead Wires
The analog multimeter gets its readings from two lead wires that are connected to its body. One of these wires is red and is plugged into the port that reads "Ohms." The black lead wire should be plugged into the port that reads "Com."
Step 3 - Calibrate the Meter Reading
Once the two leads are plugged into the analog multimeter, you should calibrate it so you can take an accurate reading. Touch the two leads together and see what the needle does. It should display some sort of reading. It may say something like 1.5 ohms. You need to do this every time, as this reading can change due to atmospheric conditions and moisture. Record this number on a piece of paper for future use.
Step 4 - Check the Circuit
Every piece of electronic equipment has specifications written on a tag. Whatever the number is, this is the number you should read when you test the circuit. Remove all other electrical power from the device before you test it.
Step 5 - Disconnect the Power Wires
Just unplugging a device is not enough to shut it down completely. In order to get an accurate reading, you will need to use a screwdriver to remove any other wires that supply some sort of power to the electronic device. Any wires that are still connected can give off a false reading that will make it seem like something is wrong when nothing may be.
Step 6 - Test the Circuit
Turn on the analog multimeter and set the selector switch to "ohms." Touch the red lead to the positive portion of the electronic coil or device. Touch the black lead to the negative or ground wire. The needle on the analog multimeter will jump to register a reading. When it does, you will want to wait a few seconds for the needle to shop moving.
Step 7 - Take the Reading
After the needle stops moving, you can read the number it is pointing to. Write that number down and then subtract the 1.5 initial reading from it. The number you are left with is the ohms reading for that device.