Advanced Features of Digital Multimeters
From control circuits to small embedded computers, integrated circuits enable more functionality in modern digital instruments.
Common measures of enhancement include:
Current-limited semiconductor junction voltage drop measurement to determine transistor type;
Graphical display of measured quantities, such as histograms;
can make go/no-go measurements easier;
Continuous measurement, and sound alarm when the circuit occurs;
low frequency oscilloscope;
Telephone test device;
Automatic circuit test, including automatic timing, delay signal, etc.;
Simple data detection functions, such as recording the maximum and minimum readings for a specified period, or obtaining a certain amount of sample readings at regular intervals
Sample and hold, which locks the last reading for reading after the device is removed from the test circuit;
The test range is automatically converted, and the meter automatically selects the appropriate measurement range during measurement to protect the meter from damage.
A digital multimeter usually has circuitry or software to ensure accurate measurement of AC voltage at any frequency. This type of multimeter combines the input signal using the root mean square method, so that even if the input signal is not an ideal sine wave, the true voltage value can be read correctly.
Some modern multimeters can be connected to a personal computer via infrared, RS-232 or IEEE-488 device bus, etc. In these ways, the computer can record the readings as they are being measured, or a set of results can be uploaded from the device to the computer.
As modern devices and systems become more complex, the multimeter is becoming less common in the technician's toolbox; more complex and specialized equipment is taking its place. For example, while originally measuring an antenna, a worker might use an ohmmeter to measure its resistance; a modern technician might use a handheld analyzer to test several parameters to determine the integrity of the antenna cable.
