CHAPTER 4
Digital Multimeter
We’re still covering basic prerequisites to building a robot, such as safety and where to buy parts. In this
chapter, you’re going to learn about a vital piece of measurement equipment that every robot builder has by
their side, the digital multimeter. Multimeter features are broken into groups: must-have, nice-to-have, and
optional. The chapter concludes with an analysis of three multimeters.
A multimeter is a required tool for robot building. You will need a multimeter to perform the
experiments and build the projects in the chapters that follow. (See Figure 4-1 for an example of a
multimeter).
With a multimeter, you can:
- determine if an unexpected amount (too much or too little) of power is being used
- determine if a part is damaged or worn out
- determine what type of part something is
- determine the value (electrical denomination) of a part
- manually read sensors and chips to aid designing and debugging
The capabilities of digital multimeters (also called DMMs) have rocketed while prices have dropped.
A perfectly acceptable digital multimeter can be had for under $20. A really great digital multimeter can be
had for $150.
What follows are brief descriptions of the features available on multimeters. Don’t worry too much
about what the fancy symbols (m,W) stand for, as they’re written that way so that they’ll match the catalogs
and advertisements.
If this information seems overwhelming to you, just buy (or borrow) any cheap, digital multimeter until
you’ve learned enough to make a more educated purchase.
Must-Have Features
Here are the features your multimeter must have: