# Multimeters ## Overview https://www.youtube.com/watch?v=rPGoMbVSUu8 The most important debugging tool in any E.E.'s toolbox is a trusty multimeter. A multimeter can measure continuity, resistance, voltage and sometimes even current, capacitance, temperature, etc. It's a swiss army knife for geeks!## What to look for? Everyone always asks, " **What multimeter should I get?"** Well, since they're rather commodified (there are dozens of manufacturers) it is hard to make everyone use the same model, even though it would make things easier. These are the necessities: - Continuity testing with piezo buzzer - Resistance test down to 10 ohm (or lower) and up to 1 Megaohm (or higher) - DC voltage test down to 100mV (or lower) and up to 50V - AC voltage test down to 1V and up to 400V (or 200V in the US/Canada/Japan) - Diode testing Here are nice things to have in your meter - Auto-off - to keep from draining the batteries - AC and DC current test, from 10mA to maybe 200mA and then also a 10A one as well - Stand - a thing that flips out and keeps it upright on your table - Auto-ranging - note: some people don't like auto-ranging because its slower and not as precise - Hold - keep the maximum value on the screen so you can probe without looking at the meter. - Common battery - such as 9V or AA's, pocket meters use hard-to-replace coin cells These are things that I rarely (if ever) use, in descending order - Frequency counter - before I had a scope this was surprisingly useful! - Capacitance testing - usually to check random SMT caps - Inductance testing - how often do you really use an inductor? - Duty cycle - never used this - Transistor beta meter - people don't really work with transistors anymore - Temperature probe - I use the "Pease temperature test": a finger ## Other Useful Resources - [TangentSoft's half-hour video tutorial](http://tangentsoft.net/elec/movies/tt06.html "Link: http://tangentsoft.net/elec/movies/tt06.html") - [Make Magazine's Bre & Joey Grand on how to use a multimeter](http://www.makezine.com/blog/archive/2007/01/multimeter_tuto.html "Link: http://www.makezine.com/blog/archive/2007/01/multimeter\_tuto.html") - [Robot Platform tutorial on using digital multimeter](http://www.robotplatform.com/tools/multimeter/multimeter.html "Link: http://www.robotplatform.com/tools/multimeter/multimeter.html") - [Next Page](https://learn.adafruit.com/multimeters/continuity.md) ## Featured Products ### Extech EX330 12-function autoranging multimeter [Extech EX330 12-function autoranging multimeter](https://www.adafruit.com/product/308) **Discontinued** - [you can grab this Digital Multimeter - Model 9205B+ instead!](https://www.adafruit.com/product/2034) If you're looking for one of the best multimeters, we're proud to now offer our personal favorite! The Extech EX330 "12... No Longer Stocked [Buy Now](https://www.adafruit.com/product/308) [Related Guides to the Product](https://learn.adafruit.com/products/308/guides) ### Digital Multimeter [Digital Multimeter](https://www.adafruit.com/product/71) This is a basic multimeter, I've played with it a bunch and I think its a great addition to a toolbox. It's low cost and simple to use with a big clear display and all the measurements you need: - AC/DC Voltage measurement - Current measurement, from 1uA up to... No Longer Stocked [Buy Now](https://www.adafruit.com/product/71) [Related Guides to the Product](https://learn.adafruit.com/products/71/guides) ### Digital Multimeter - Model 9205B+ [Digital Multimeter - Model 9205B+](https://www.adafruit.com/product/2034) This massive multimeter has everything but the kitchen sink included. It's a great addition to any workbench or toolbox.  It's low cost, simple to use, and has a big clear display with all the measurements you need and more! The multimeter includes: - AC/DC Voltage... In Stock [Buy Now](https://www.adafruit.com/product/2034) [Related Guides to the Product](https://learn.adafruit.com/products/2034/guides) ### Pocket Autoranging Digital Multimeter [Pocket Autoranging Digital Multimeter](https://www.adafruit.com/product/850) When we're on the go, we like to keep a multimeter in our purse and this model is by far the best pocket meter we've found. It's so good you'll end up using it as your main multimeter! First up, this meter can measure nearly everything: it's got DC and AC... In Stock [Buy Now](https://www.adafruit.com/product/850) [Related Guides to the Product](https://learn.adafruit.com/products/850/guides) ### Multi-Meter! - Skill badge, iron-on patch [Multi-Meter! - Skill badge, iron-on patch](https://www.adafruit.com/product/502) You can use a multi-meter! Adafruit offers a fun and exciting "badges" of achievement for electronics, science and engineering. We believe everyone should be able to be rewarded for learning a useful skill, a badge is just one of the many ways to show and share. This is... No Longer Stocked [Buy Now](https://www.adafruit.com/product/502) [Related Guides to the Product](https://learn.adafruit.com/products/502/guides) ### Multi-Meter! - Sticker! [Multi-Meter! - Sticker!](https://www.adafruit.com/product/646) You can use a multi-meter! Adafruit offers a fun and exciting stickers to celebrate achievements in electronics, science and engineering. We believe everyone should be able to be rewarded for learning a useful skill, a great sticker is just one of the many ways to show and share. No Longer Stocked [Buy Now](https://www.adafruit.com/product/646) [Related Guides to the Product](https://learn.adafruit.com/products/646/guides) ## Related Guides - [USB-PD Hacks](https://learn.adafruit.com/usb-pd-hacks.md) - [Ladyada's Toolkit](https://learn.adafruit.com/ladyadas-toolkit.md) - [Energy Budgets](https://learn.adafruit.com/energy-budgets.md) - [Hacking Yoto Music Players](https://learn.adafruit.com/hacking-the-yoto-music-players.md) - [Collin's Lab: Multimeters](https://learn.adafruit.com/collins-lab-multimeters.md)