Meters are used to measure units of electricity. This includes voltage, current and some multimeters also support resistance. Some are analog, which have a pointer that moves with a magnetic force. Others are digital which has a numerical display and often have a analog-to-digital converter.
Analog meters use magnets to move the pointer. An objective of this design is to draw as little current as possible. When a meter operates on the electrostatic principle it use the repulsion between two charge plates to deflect a pointer attached to a spring.
Digital meters utilize analog –to-digital converter known as an integrating convert. Often, digital meters have amplifiers.
A voltmeter is a tool that measures electrical potential difference between two points in a circuit. Analog voltmeters have a pointer that moves across a scalein proportion to the voltage circuit. Digital voltmeters use a numerical display of voltage by using an analog to digital converter. These meters can come along with other meters in the form of a multimeter.
These meters can measure anything from a small percentage of a volt to several thousand volts. When a meter is paired with an amplifier, the meter can measure microvolts or even smaller.
An ammeter is similar to a voltmeter; however it measures current instead of voltage. Ammeters used for small units, such as milliampere or microampere, are referred to as milliammeter and microammeter.
Like voltmeters, ammeters come in both analog and digital.
These meters measure both Voltage and current, some also measure resistance. Multimeters are usually digital now a days; however, there are some that are analog multimeters as well.