Electrical Motor Controls, Chapters 21-22

A voltage-output pressure sensor typically outputs 0 VDC to _____ VDC proportional to the rating of the pressure sensor.

10

A current-output pressure sensor typically outputs 4 mA to _____ mA proportional to the rating of the pressure sensor.

20

The high-frequency sound waves of an ultrasonic sensor are typically in the _____ kHz range.

200

Cold resistance is measured at _____ °C. A. 5 B. 15 C. 25 D. 35

25

_____ sensors can detect materials such as plastic, glass, water, moist wood, etc.

Capacitive

Pressure sensors are suited for a wide variety of pressure measurements on _____, pumps, and other similar equipment.

Compressors

The _____ flowing through a photodiode increases as the resistance decreases.

Current

_____ mode is a method of ultrasonic sensor operation in which the emitter and receiver are placed opposite each other so that the sound waves from the emitter are received by the receiver.

Direct

The operation of a thermistor is based on the _____ -hole theory. A. electron B. proton C. neutron D. positron

Electron

_____ is a ratio of the amplitude of an output signal to the amplitude of an input signal.

Gain

A(n) _____ sensor detects the proximity of a magnetic field.

Hall effect

_____ actuation is an active method of Hall effect sensor activation in which a magnet is oriented perpendicular to the surface of the sensor and is usually centered over the point of maximum sensitivity.

Head-on

_____ and contamination are the primary causes of photocell failure. A. Humidity B. Overheating C. Voltage swells D. Transient voltages

Humidity

_____ heated thermistors are used for precision temperature measurement and temperature compensation. A. Directly B. Indirectly C. Chemically D. Mechanically

Indirectly

The primary difference between a photodiode and a regular diode is that a photodiode has an addition of a _____ in it's housing for focusing light on the PN junction.

Lens

A photoconductive cell (photocell) is a device that conducts current when energized by _____. A. temperature B. humidity C. sound D. light

Light

With a(n) _____ thermistor, an increase in temperature causes the resistance of the thermistor to decrease. A. NTC B. PTC C. NPN D. PNP

NTC

_____ error is a slight mismatch between internal components.

Offset

Without light, the _____ of the photodiode is high.

Resistance

A photocell is, in effect, a variable _____. A. amplifier B. resistor C. transistor D. transformer

Resistor

A thermistor is a(n) _____-sensitive resistor. A. airflow B. sound C. temperature D. light

Temperature

A flow detection sensor operates on the principle of _____ conductivity.

Thermal

An op amp is often used in digital circuits that require the _____ amplification of a weak signal.

analog

Hall voltage varies depending on how close the magnet is to the Hall generator, which acts as a(n) _____ signal.

analog

In any transistor circuit, the _____ junction must always be forward biased.

base/emitter

A _____ device is a device in which both holes and electrons are used as internal carriers for maintaining current flow.

bipolar

Amplifiers connected together are called _____ amplifiers.

cascaded

A(n) _____ system may have automatic correction control.

closed-loop

Generally, any material with a _____ constant greater than 1.2 may be detected.

dialectric

The _____ provides wide bandwidth and high impedance in an op amp.

differential amplifier

Inductive proximity sensors operate on the _____ principle.

eddy current killed oscillator

A proximity sensor (proximity switch) is a solid-state sensor that detects the presence of an object by means of a(n) _____ sensing field.

electronic

The input of a common-_____ circuit is across the base and emitter, while the load is across the collector and emitter.

emitter

Since a(n) _____ MOSFET does not conduct at zero gate voltage, it is often called a normally off MOSFET.

enhancement

The main body of a(n) _____ MOSFET is composed of a highly resistive P-type material.

enhancement

The two sections of P-type material constitute the _____ of a JFET.

gate

Problems with IGBTs and other solid-state switches can be reduced by keeping their _____ clean for proper airflow movement.

heat sinks

JFET's are used extensively in circuits where low power and high _____ are factors.

impedance

A(n) _____ proximity sensor is a sensor that detects only conductive substances.

inductive

The _____ resistance measurments taken when troubleshooting IGBT's are used to determine whether the resistance is too low and the device is defective.

leakage

Hall effect sensors are also used to replace mechanical _____ switches in applications that require the detection of an object's position.

limit

Because there is a small delay (usually less than 30 sec) before a flow detection sensor heats enough to signal no flow, the sensor acts like a _____, which allows for a short time delay to pass before signaling a problem.

motor starter overload

Typical Hall effect sensor package configurations include cylinder, proximity, vane, and ____.

plunger

One disadvantage of an IGBT is that the switching speed is inferior to that of a(n) _____ MOSFET.

power

Materials such as foam, fabric, and _____ are difficult for ultrasonic sensors to detect and are better detected by photoelectric or proximity sensors.

rubber

A flow detection sensor is a sensor that detects the movement (flow) of liquid or gas using a(n) _____.

solid-state device

A JFET is a(n) _____ device.

unipolar

The main difference in operation between a JFET and MOSFET is that _____ is applied between the gate and the P and N regions of the MOSFET structure.

voltage

A _____ is a noninverting amplifier.

voltage follower