TABLE OF CONTENTS Scott Stever
Agilent Technologies
Loveland, Colorado
Voltage (both ac and dc), ac and dc current, and resistance are common quantities measured by electronic instruments. Meters are the easiest to use instrument for performing these measurements. In the simplest case, each measurement type is performed by an individual instrument a voltmeter measures voltage, an ammeter measures current, and an ohmmeter measures resistance. These instruments have many elements in common. A multimeter combines these instruments and sometimes others together into a single general-purpose multifunction instrument.
There are two primary types of meters general purpose and specialty. General-purpose meters measure several types of electrical parameters such as voltage, resistance, and current. A digital multimeter (DMM) is an example of a common variety of general-purpose meter. Specialty meters are generally optimized for measuring a single parameter very well, emphasizing either measurement accuracy, bandwidth, or sensitivity. Each type of instrument is tuned for a different group of users and measurement applications. Table 13.1 presents a comparison of various types of meters and selected measuring capabilities.
| Type of meter | Multifunction | Measuring range | Frequency range | Speed, max readings/second | Best accuracy | Digits | Price range |
|---|---|---|---|---|---|---|---|
| General Purpose | |||||||
| Handheld DMM | Y | 10 V 1000 V 1 nA 10 A 10 m ? 50 M ? | 20 Hz 20 kHz | 2 | 0.1% | 3 1/2 4 1/2 | $30 $400 |
| Bench DMM | Y | 10 V 1000 V 1 nA 10 A 10 m ? 50 M ? | 20 Hz 100 kHz | 10 | 0.01% |
