Multimeters (handheld)
Multimeters are electrical measuring devices, most can measure voltage, current, and resistance (not at the same time). Some have more functions, this page will cover the basics. The Makerspace has a selection of digital multimeters (DMMs) available for use. They all function on the same basic principles but many have slightly different layouts - check the settings and set up one more time if something isn't working! Makerspace employees are also available to help.
Please remember to turn off the DMM after you are done to conserve battery life.
Voltage:
Multimeters can measure AC and DC voltage, in the Makerspace you'll probably be testing DC voltage values. To test for voltage, put the leads in parallel with the component of interest.
While some multimeters have an autorange function, it is also common to set a range on your multimeter to achieve the resolution required. This means you should have an idea of the voltage you're looking for.
Resistance:
Disconnect the component of interest from any power source before testing for resistance. Touch one lead to one end of your component and the other to the other end, polarity does not matter. The resistance of the component will becalculated by the DMM as its internal batteries send a very small current through the unknown resistance, internal resistors, and current meter. When the leads are not attached the DMM will displayOL (overload), or I (infinite). If the leads are touching each other, the display will show a very low or 0Ω resistance.
Current:
Before setting up a current test make sure the circuit has no power flowing through it to minimize the risk of an electric shock!
To test for current, break your circuit (safely), and insert the multimeter in series in the area of interest. Connect your circuit to the power source. Record the current reading. Do not put the multimeter in parallel here - it has negligible resistance and will short your circuit! This can damage your circuit, the multimeter, and potentially harm you if it arcs!
The Makerspace has a few clamp style current measuring devices. Please ask a staff member if you think your project requires a DMM with this capability and we will help with creating a safe testing procedure.
Continuity:
Many DMMs have a continuity setting denoted with this symbol 
. If a section of a circuit is continuous, the multimeter will beep when both leads
are attached.