Multimeter

Purchase from a manufacturer or other distributor.

Build

You can buy this tool from Fluke or ExTech. The anticipated price range is $51 - $100.

About this tool
Description	Multimeters are the most common and useful electronics tool. They are used for measuring voltage, current, resistance, frequency, capacitance, and continuity in electronic circuits. Largely depends on the manufacturer and intended range. Industrial multimeters are incredibly accurate and have a large range (e.g. 0 - 1000V and 0.01uA - 10A), but this comes at an increased cost. For hobbyist applications, a multimeter between $20 and $60 should be sufficient. These will have a range ~ 0 to 500V and ~ 0.1uA to 400/ 500 mA. This tool is recommended for lending libraries.
Ideal Age Group	Elementary school (6 - 10 years), Middle school (11 - 13 years), High school (14 - 17 years), College, Graduate students, Adults, Families, Seniors (With proper training, this is a very easy and versatile tool to use. The only caveat would be if an individual is working with high voltage -- in this case, it would only be recommended for folks with professional experience and training.)
Training	Learning materials are available online.
Size & weight	Small: This tool would fit in a 6 inch cube. Between 13oz and 1lb (4 sticks of butter weigh about 1lb)
Expected lifetime	Should last more or less forever
Topics	Computers & Technology, Physics
Activities	At school, At a science center, zoo or aquarium, At night, At home
Tool updated	May 9, 2017, 7:20 a.m.