Chapter 5 Measurement Decices Flashcards
The degree to which a measurement confirms to a specific standard
Accuracy
The level of accuracy or mechanical exactness
Precision
The verification of graduations and incremental values of a precision measuring instrument for accuracy and adjustments
Calibration
A semiprecision measuring tool used for measuring length
Rule
A hand tool with one fixed and one adjustable jaw used for making precision measurements
Caliper
A short auxiliary scale placed along the main scale of an instrument to provide accurate fractional readings
Vernier scale
A precision measuring instrument used to take high accuracy inside, outside or depth measurements
Micrometer
Measurement of the intensity of heat
Temperature
A device used for taking temperature measurements at a single pt. by direct contact
Contact temperature probe
A thermal expansion, temperature measuring device consisting of a sealed, narrow-bore glass tube with a bulb at the bottom filled with a liquid
Liquid-in-glass Thermometer
Uses a strip consisting of two alloys with different coefficients of thermal expansion that are fused together and formed into a single strip and a pointer mechanism calibrated for temperature reading
Bimetallic Thermometer
A device that produces electricity when two different metals that are twisted together are heated
Thermocouple
A device that measures infrared energy emitted by a material and displays the temperature as a numerical value
Infrared Temperature Meter
A device that detects heat levels from infrared energy emitted without making direct contact and displays the temperature as an image
Thermal Imager
A device that consists of two glass thermometers attached to an assembly that permits the two thermometers to be rotated through the air
Sling psychrometer
a humidity analyzer that uses two thermometers one with a wet bulb and one dry
Psychrometer
a humidity analyzer that measures the physical or electrical changes in various materials
Hygrometer
a material that changes its physical size or electrical characteristics as the humidity changes
hygroscopic element
an anodized aluminum strip with a porous aluminum oxide layer used as a dielectric
capacitance probe
a portable electrical device that precisely measures positive, negative or differential pressures in small increments
Digital Manometer
a mechanical pressure gauge with a curved tube made of thin metal that acts as a pressure-sensing element
Bourdon tube pressure gauge
a mechanical pressure gauge that has a small single-acting spring return cylinder that acts as a pressure-sensing element
Schrader pressure gauge
a mechanical pressure gauge consisting of two pressure-tight compartments, a flexible diaphragm, a biasing spring, and a magnetic pointer
Magnehelic pressure gauge
the speed at which gases, liquids or solids travel through a system
Velocity
a device that measures average air velocity or average airflow rate
Anemometer
a device that is placed over a grill or diffuser to measure the rate of airflow
Flow Hood
used to measure velocity pressures in a duct, by measuring the static and total pressures in the duct
Pilot Tube
a permanently installed air-handling system device used to measure air velocity in a duct
Thermoanemometer
a meter that can measure two or more electrical properties and displays the measured properties along calibrated linear and nonlinear scales using a pointer
Analog Multimeter
a meter that measures two or more electrical properties and displays the measured properties as numerical values
Digital Multimeter (DMM)
used to measure current and resistance
Ohmmeter
are produced by the magnetic fields generated by current-carrying conductors, fluorescent lighting, and operating electrical equipment
Ghost Voltages
a meter that measures the current in a circuit by measuring the strength of the magnetic field around a single conductor
Clamp-On Ammeter
an instrument that tests for a complete path for current to flow
Continuity Tester
a meter that detects insulation deterioration by measuring high resistance values under high-voltage test conditions
Megohmmeter
an instrument that indicates approximate voltage levels and type through the movement and vibration of a pointer on a scale
Voltage Tester
an instrument that is plugged into a standard receptacle to determine when the receptacle is properly wired and energized
Receptacle Tester
a special DC voltmeter that detects the presence or absence of a digital signal
Digital Logic Probe
an instrument used to measure ground resistance for grounding rod installations
Ground Resistance Tester
a device used to determine phase sequence and open phases
Phase sequence Indicator
an instrument used to measure the speed of rotation of a shaft or wheel in rpm
Tachometer
used to pinpoint refrigerant leaks
Soap Bubbles
a device used to detect the presence of halogen gas
Electronic Leak Detector
uses UV light to detect fluorescent dye refrigerant leaks
Fluorescent Leak Detector
detects sounds created by refrigerant leaks
Ultrasonic Leak Detector
a stationary detector system for one specific type of refrigerant
Fixed Leak Detector
