Sensors Flashcards

1
Q

it detects the magnitude of a physical parameter and changes it into a signal that can be processed by the system

A

sensor

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2
Q

an active element of a sensor that is responsible for converting energy from one form to another

A

transducer

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3
Q

type of transducer that coverts physical quantities into mechanical

A

mechanical transducer

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4
Q

type of transducer that coverts physical quantities into electrical

A

electrical transducer

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5
Q

what are the two types of transducer?

A

mechanical and electrical transducer

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6
Q

these sensors require an external power source to operate

A

active sensors

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7
Q

these sensors generate an electric current in response to an external stimulus without the need of additional energy source

A

passive sensors

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8
Q

it detects the temperature of its surroundings and transforms the data into electronic output

A

temperature sensor

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9
Q

Two dissimilar metals in contact form a thermoelectric junction that produces a voltage proportional

A

thermocouple

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10
Q

why does thermoelectric junctions occur in pairs?

A

Because an electrical circuit must form a closed loop

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11
Q

it is a metallic wire wound around a ceramic or glass core and hermetically sealed.

A

resistance temperature detector/ device (RTD)

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12
Q

it is a semiconductor device, available
in probes of different shapes and sizes, whose
resistance changes exponentially with temperature.

A

thermistors

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13
Q

what are the two types of thermistor?

A

negative temperature coefficients (NTC) and positive temperature coefficients (PTC)

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14
Q

this thermistor’s resistance decreases as its temperature increases. it is also commonly used for temperature measurement.

A

NTC thermistors

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15
Q

this thermistor’s resistance increases as its temperature increases and is primarily used for circuit protection.

A

PTC thermistors

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16
Q

In this temperature-sensor the forward ac voltage change or the forward ac current change at the pn junction diode due to the temperature change is measured for a constant amplitude of superimposed ac small signal of current δI or voltage δV, respectively, on the constant forward dc current I0

A

p-n junction temperature sensor

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17
Q

are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade)
temperature.

A

LM35 temperature sensor

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18
Q

It is composed of two or more metal layers having different coefficients of thermal expansion.

A

bimetallic strip

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19
Q

in a bimetallic strip, the layers are permanently bonded together. will its structure deform when the temperature changes? (yes or no)

A

yes

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20
Q

__________ are those sensors that detect electromagnetic radiation in what is generally understood as the broad optical range—from far Infrared to Ultraviolet.

A

optical sensors

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21
Q

this type of optical sensor is a resistor whose resistance depends on the intensity of light.

A

light dependent resistor
LDR
photoresistor

22
Q

this resistor’s resistance is very high but dramatically drops when exposed to light

A

light dependent resistor
LDR
photoresistor

23
Q

this is a light-sensitive transistor. one of its types is a photobipolar.

A

phototransistor

24
Q

it is a device that converts motion into a sequence of digital pulses. By counting a single bit or decoding a set of bits, the pulses can be converted to relative or absolute position measurements.

A

optical encoder

25
Q

emits a light beam (visible or infrared) from its light-emitting element.

A

photoelectric sensor

26
Q

a type of photoelectric sensor that is used to detect the light beam reflected from the target

A

reflective type photoelectric sensor

27
Q

a type of photoelectric sensor that is used to measure the change in light quantity caused by the target crossing the optical axis.

A

thrubeam type sensor

28
Q

a type of photoelectric sensor that light from the emitting element hits the reflector and returns to the light receiving element. When a target is present, the light is interrupted.

A

retroreflective type sensor

29
Q

it is a non-contact sensor that detects the presence of an object (often referred to as the “target”) when the target enters the sensor’s field.

A

proximity sensor

30
Q

detection of metallic objects (type of proximity sensor)

A

inductive sensors

31
Q

Detection of metallic and non-metallic objects (Liquids, plastics, woods). (type of proximity sensor)

A

capacitive sensors

32
Q

a type of proximity sensor that use light sensitive elements to detect objects.

A

photoelectric sensors

33
Q

a type of proximity sensor that detects the presence of permanent magnets

A

magnetic sensors

34
Q

consist of two flat ferromagnetic reeds sealed in an inert atmosphere within a glass capsule.

A

reed switch

35
Q

A special kind of variable resistor, whose electrical resistance depends on the external
magnetic force applied

A

magneto resistor

36
Q

it is a transducer used for measuring linear displacement. It consists of primary and secondary windings and a movable iron core. It functions much like a transformer, where
voltages are induced in the secondary coil in
response to excitation in the primary coil.

A

linear variable differential transformer/transducer

37
Q

The simplest kind of displacement sensor is
a mechanical switch which returns one bit of
information: touching or not touching.

A

mechanical switch

37
Q

these are devices that are activated
by an external magnetic field. The output signal from it is the function of magnetic field
density around the device.

A

hall effect sensor

38
Q

The most common transducer for
experimentally measuring strain in a
mechanical component is the bonded metal foil strain gage

A

strain gauge/strain gage

39
Q

what are the 3 types of strain gage assembly?

A

uniaxial
biaxial
strain gage rosette

40
Q

devices that measure acceleration, which is the rate of change of the velocity of an object.

A

accelerometer

41
Q

Some materials (such as natural quartz crystal, silicon dioxide, barrium titanite, lead zirconate titanate (PZT)), called piezo crystals, produce a charge in response to a force (or deformation) applied to them.

A

piezoelectric accelerometer

42
Q

A _________ can be built by using a permanent magnet as a mass on a spring or cantilever beam and sense the field of the permanent
magnet using a Hall element or magnetoresistive sensor

A

magnetic accelerometers

43
Q

it is a sensor or a transducer that converts a load or force acting on it into an electronic signal. This electronic signal can be a voltage change, current change or frequency change depending on the type of load cell and circuitry used

A

load cell

44
Q

a process technology used to create tiny
integrated devices or systems that combine
mechanical and electrical components.

A

micro-electromechanical systems (MEMS)

45
Q

have the ability to sense, control and actuate on the micro scale, and generate effects on the macro scale.

A

MEMS

46
Q

One of the simplest and least expensive ways to measure rotational or linear motion.

A

potentiometer

47
Q

made of a pyroelectric sensor (which you can see above as the round metal can with a rectangular crystal in the center), which can
detect levels of infrared radiation. Everything emits some low level radiation, and the hotter something is, the more radiation is emitted

A

PIR sensor

48
Q

sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone)

A

ultrasonic distance sensor

49
Q

The effect by which a thermoelectric junction of dissimilar metals produces a voltage relative to temperature

A

seebeck effect