Measuring Devices Flashcards
Sometimes electric current is measured by the event of heat it produces in a resistance. Such meters work by __________ principles.
Thermal Heating
Many measuring devices work because electric and magnetic fields produce forces proportional to the intensity of the field. By using s tension spring against which the electric force can pull or push a movable needle can be constructed. The needle can then be placed in front of s calibrated scale allowing a direct reading of the quantity to be measured.
Electromagnetic Deflection or Electrostatic Deflection
Sometimes meters work by means of small motors whose speed depends on the measured quantity. The rotation rate or number of rotations given in a certain time can be measured or counted. These are forms of __________.
Rate Meters
Meters that count electrical pulses.
Electronic Counters
Wrapping a wire in a coil around a compass resulted in a device that could detect an electric current. This effect is known as _________ and the device is called the ____________.
Galvanism
Galvanometer
The most common devices for demonstrating electrostatic forces is the __________.
Electroscope
A meter with a coil attached right to the meter pointer, and suspended by means of a spring in the field of the magnet is called a __________ and is the basic principle of the __________.
D’Arsonval Movement
Ammeter
A meter that measures the pressure of charge carriers or EMF is called ___________.
Voltmeter
Meters that measure resistances are called _____________.
Ohmmeters
A Volt-Ohm-Milliammeter or VOM is called a ____________.
MULTIMETER
A voltmeter that uses a vacuum tube amplifier to minimize the current drain is called a ___________.
Vacuum Tube Volt Meter or VTVM
Meters used to measure Power are called __________.
Wattmeters
Utility companies use ___________ to measure the amount of power that we use.
Watt Hour Meters
Meters that provide a direct readout without the possibility of interpolation are called ___________.
Digital Readout Meters or Digital Meters
Meters used to count pulses in a manner similar to the way the utility meter counts the number of turns of a motor are called ___________.
Frequency Counters
