Editing Multimeter (section)

=== Digital ===
[[File:Benchtop multimeter.jpg|thumb|A bench-top multimeter]]
[[File:PowerbankEnergizerQE10007PQ20210904191417pixelated20210905.jpg|thumb|USB-powered multimeter for examining [[battery charging]] of [[portable electronics]]]]
[[File:Fluke87-V Multimeter.jpg|thumb|upright=.6|A {{frac|4|1|2}}-digit digital multimeter]]

Digital instruments, which necessarily incorporate amplifiers, use the same principles as analog instruments for resistance readings. For resistance measurements, usually a small constant current is passed through the device under test and the digital multimeter reads the resultant voltage drop; this eliminates the scale compression found in analog meters, but requires a source of precise current. An autoranging digital multimeter can automatically adjust the scaling network so the measurement circuits use the full precision of the A/D converter.

In a digital multimeter the signal under test is converted to a voltage and an amplifier with electronically controlled gain preconditions the signal. A digital multimeter displays the quantity measured as a number, which eliminates [[parallax]] errors.

Modern digital multimeters may have an [[embedded computer]], which provides a wealth of convenience features. Measurement enhancements available include:

* Auto-ranging, which selects the correct range for the quantity under test so that the most [[significant digits]] are shown. For example, a four-digit multimeter would automatically select an appropriate range to display 12.34 mV instead of 0.012 V, or overloading. Auto-ranging meters usually include a facility to hold the meter to a particular range, because a measurement that causes frequent range changes can be distracting to the user.
* Auto-polarity for direct-current readings, shows if the [[electric polarity]] of applied voltage is positive (agrees with meter lead labels) or negative (opposite polarity to meter leads).
* [[Sample and hold]], which will latch the most recent reading for examination after the instrument is removed from the circuit under test.
* Current-limited tests for [[voltage drop]] across [[P-n junction|semi conductor junctions]]. While not a replacement for a proper [[transistor tester]], and most certainly not for a swept [[curve tracer]] type, this facilitates testing diodes and a variety of transistor types.<ref>{{cite web|last=Goldwasser|first=Samuel| url=http://www.repairfaq.org/sam/semitest.htm#stttm|title=Basic Testing of Semiconductor Devices|access-date=2007-01-28}}</ref>
* A graphic representation of the quantity under test, as a [[bar graph]]. This makes go/no-go testing easy, and also allows spotting of fast-moving trends.
* A low-bandwidth [[oscilloscope]].<ref>{{cite web|last=Extech Instruments|url=http://www.extech.com/instrument/products/310_399/381295_381296.html | access-date = 2007-01-28|title=Extech 5&nbsp;MHz Dual Channel Multiscope}}</ref>
* Automotive circuit testers, including tests for automotive timing and dwell signals (dwell and engine rpm testing is usually available as an option and is not included in the basic automotive DMMs).
* Simple [[data acquisition]] features to record maximum and minimum readings over a given period, or to take a number of [[Sample (statistics)|samples]] at fixed intervals.<ref>{{cite web |series=Extech Instruments | url = http://www.extech.com/instrument/products/310_399/380900.html | access-date = 2007-01-28 |title=Extech Dual Channel, Datalogging multimeter |archive-url=https://web.archive.org/web/20070403235544/http://www.extech.com/instrument/products/310_399/380900.html |archive-date=2007-04-03}}</ref>
* Integration with tweezers for [[surface-mount technology]].<ref>{{cite web|last=Siborg Systems Inc|url=http://www.siborg.com/smarttweezers| access-date = 2008-04-23|title=Digital Multimeter Smart Tweezers from Siborg}}</ref>{{Better source needed|reason=Citation given is a primarily commercial website. Surely, a better source must be available.|date=January 2015}}
* A combined [[LCR meter]] for small-size SMD and through-hole components.<ref>{{ cite web | last = Advance Devices Inc | url = http://www.advancedevices.com/docs/SmartTweezersDs.pdf | archive-url = https://web.archive.org/web/20070109171501/http://www.advancedevices.com/docs/SmartTweezersDs.pdf | url-status = dead | archive-date = 2007-01-09 | access-date = 2009-01-20 | title = Smart Tweezers Digital Multimeter/LCR Meter }}</ref>

Modern meters may be interfaced with a [[personal computer]] by [[IrDA]] links, [[RS-232]] connections, [[USB]], [[Bluetooth]], or an instrument bus such as [[IEEE-488]]. The interface allows the computer to record measurements as they are made. Some DMMs can store measurements and upload them to a computer.<ref>{{cite web|last=Fluke Manufacturing | url = http://support.fluke.com/find-sales/download/asset/2386842_a_w.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://support.fluke.com/find-sales/download/asset/2386842_a_w.pdf |archive-date=2022-10-09 |url-status= live | title = Logging and analyzing events with FlukeView Forms Software|access-date=2007-01-28}}</ref>