Multimeters:
A multimeter, multitester, or a VOM (Volt-Ohm meter), is an electronic measuring instrument which combines several measurement functions into one unit. It is used for basic fault finding and field service work, or to measure at a very high degree of accuracy. They can be used to troubleshoot electrical problems in a wide array of industrial and household devices such as electronic equipment, motor controls, domestic appliances, power supplies, and wiring systems.
Digital multimeters (DMM, DVOM) display the measured value in numerals, which eliminates parallax errors, and may display a bar of a length proportional to the quantity being measured. Modern multimeters are often digital due to their accuracy, durability and extra features. In a digital multimeter the signal under test is converted to a voltage and an amplifier with electronically controlled gain preconditions the signal.DMMs are able to offer as standard the basic measurements that would typically include:
- Current (DC) -(Typically low current without an amp probe)
- Current (AC)-(Typically low current without an amp probe)
- Voltage (DC)
- Voltage (AC)
- Resistance
- Most DMMs are able to offer additional test capabilities. These may include some of the following:
- Capacitance
- Temperature
- Frequency
- Transistor test – hfe, etc
- Continuity (buzzer)
- Auto-ranging-selects the correct range for the quantity under test so the most significant digits are shown.
- Auto-polarity-direct-current readings, shows if the applied voltage is positive or negative
- Sample and hold-which latches the most recent reading for examination after the instrument is removed from the circuit under test.
- Current-limited tests for voltage drop across semiconductor junctions, facilitating testing diodes and a variety of transistor types.
- Graphic representation of the quantity under test making go/no-go testing simple and allows spotting of fast-moving trends.
- Low-bandwidth oscilloscope
- Automotive circuit testers, including automotive timing and dwell signals.
- Simple data acquisition features to record minimum and maximum readings over a given period, a number of samples at fixed intervals.
- Integration with tweezers for surface-mount technology.
- A combined LCR meter for small-size SMD and through-hole components.
Analog multimeters use a microammeter whose pointer moves over a scale calibrated for all the different measurements that can be made. Although multimeters are far more common, analog multimeters are still preferable in some cases, for example when monitoring a rapidly-varying value.To know more visit our site http://allindiayellowpage.com/.