A digital multimeter. Via Wikipedia.
Hi everyone! As your personal home appliance expert, one of our goals is to keep you informed on how to maintain your appliances so you can save more and have your peace of mind. You can always call us for any of your repair needs, but if you find yourself with an appliance emergency that just can’t wait, or maybe small fixes that you’d like to do yourself, you can also check our website for easy-to-understand appliance troubleshooting guides.
We’ll be posting a lot more tips and guides in the future, but first we figured it’ll be a good idea to do a basic guide on how to use a multitester, since it’s one of the most used devices when diagnosing appliance problems.
A multitester, also called a multimeter, is a device used mostly to check for voltage, current, resistance and continuity. Almost every home appliance nowadays includes an electrical component, and when these break down, most of the time you won’t be able to tell which part needs to be replaced simply by looking at it.
In most cases, you’ll be using the multitester to check for continuity or resistance. Continuity just means that there is a continuous electrical path between two points. Resistance, as the word suggests, means that there is an interference or at times, discontinuity in the electrical path.
Kinds of multitesters
An analog multitester. Via Flickr.
There are two main kinds of multitesters:
- analog – uses a needle pointer
- digital – typically uses an LCD display
Digital multitesters are more prevalent nowadays, and are pretty inexpensive. For normal household use, a multitester somewhere below $50 would do.
Parts of the multitester
Most multitesters should come with at least the following parts and functions:
- Rotary switch – this is used to select the right setting for the kind of test you’ll need to do. Often you’ll use this to turn the device on or off, choose voltage ranges in either AC or DC, or to select the amperage or Ohm setting.
- Probes – these are the two wires with needle ends that connect to the device. One is usually in black while the other one in red.
- Jacks – these are the terminals where the probes are plugged in. You’ll often see 3 which are color-coded to prevent mixup. The black probe should always be plugged into the black jack (often labelled “common”), while the red probe can be plugged in either the “amperage” terminal or “volt/ohm” terminal red jacks, depending on what kind of test you’ll need to do.
Using the multitester
You’ll only be measuring for continuity and resistance in most cases. Anything more complicated will require a professional.
When testing, you’ll first have to isolate the part that needs to tested. But before opening and taking out a part of your appliance, always make sure to unplug it first!
Testing for continuity is the same as testing for resistance, except that resistance reading is given in number of Ohms, while continuity is just indicated as a beep or a light, depending on what sort of indicator your device has.
To begin, turn the multitester on. Calibrate it by setting the rotary switch to the lowest setting for Ohms of resistance. Next, touch the two probe tips together, then turn the ADJ dial to set the pointer to zero when using an analog multitester.
Touch each terminal with a probe. Via Instructables.com
You can now use the multitester on the part you wish to test. Touch each probe to a terminal: when you get 0 Ohms of resistance, it means that there is continuity.
That’s it! One thing to remember though, it doesn’t mean that a part is broken and needs to be replaced if it has no continuity. For example, dryer cycling thermostats are designed to break continuity at certain temperatures. If it doesn’t, it won’t cut off the dryer heater, which will cause an overload. Another example would be a switch, which should only have continuity when it is switched on.