Measuring Equipment

Measuring Equipment

The electronic measuring equipment used to create stimuli and measure the performance of the devices under test (DUT for its acronym in English) .The measurement of mechanical quantities, thermal, electrical and chemical is performed using devices called sensors and transducers. The sensor is sensitive to changes in the measured variable, as a temperature, a position or a chemical concentration. The transducer converts these measurements into electrical signals, which can feed reading instruments, recording or control of the measured quantities. Sensors and transducers can operate at locations remote from the observer, as well as inadequate or impractical for humans environments.

Some devices simultaneously act as a sensor and transducer. A thermocouple consists of two joints of dissimilar metals that generate a small voltage that depends on the differential between the junctions term. The thermistor is a special resistor, whose resistance value varies with temperature. A variable resistor can convert the mechanical movement into an electrical signal. Distance measuring specially designed capacitors are used to detect light and photocell are used. To measure speed, acceleration or liquid flows are used to other devices. In most cases, the electrical signal is weak and must be amplified by an electronic circuit. Below is a list of the most important measurement is presented:

• Galvanometer: measures the change of a certain magnitude, as the intensity of current or voltage (or voltage). It is used in building analog ammeters and voltmeters.

• Ammeter and current clamp: measure the electric current.

• Ohmmeter or Wheatstone bridge: measure electrical resistance. When the electrical resistance is very high (about 1 M-ohm) or megger insulation tester is used.

• Voltmeter: measures the voltage.

• Multimeter or multimeter: measure the three magnitudes mentioned above, plus electrical continuity and the B value of the transistors (both PNP and NPN).

• Power meter: measures electrical power. It consists of an ammeter and a voltmeter. Depending on the connection settings can deliver different measurements of electrical power, as the active power and reactive power.

• Oscilloscope: measure change of current and voltage versus time.

• Logic Analyzer: test digital circuits.

• Spectrum analyzer: measures the spectral energy of the signals.

• Vector signal analyzer: as the spectrum analyzer but with digital demodulation functions.

• Electrometer: measures the electrical charge.

• Frequency or frequency: counter measures the frequency.

• Time-domain reflectometer (TDR): test the integrity of long cables.

• Capacitance meter: measures electrical capacity or capacitance.

• Electric meter: measures electrical energy. Like the power meter can be configured to measure active energy (consumed) or reactive energy.