A digital multimeter or DMM is one of the most widely used pieces of test equipment today - they are almost invaluable in any electronics laboratory, for the home, hobbyist and professional electronics engineer.
What is a digital multimeter?
For many years, analogue multimeters were used. As modern day integrated circuits were not available, these test instruments paved the way for the later digital versions
The cost of digital multimeters varies considerably. Some of these test instruments can be bought very cheaply and provide very good service and they are surprisingly accurate - far more accurate than is needed for most measurements, but top range multimeters are also available with very high specifications for use in the most demanding applications.