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Level 4 Electrical > Automated Controls > Flashcards

Automated Controls Flashcards

1
Q

Define control systems

A

Set of mechanical or electronic devices that regulate other devices or systems by way of control loops

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2
Q

Define open loop

A

Controlled only by set point commands, without feedback measurement signals. Uses one control like on/off or a timer

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3
Q

Define closed loop

A

Uses feedback signals from the system to provide automatic control and maintain specific settings. Uses two or more controls.

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4
Q

Define negative feedback

A

reduce the change or output. Dampen or buffer changes.

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5
Q

Which feedback provides system stability/equilibrium?

A

Negative feedback

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6
Q

Define positive feedback

A

increases the change or output. Enhances or amplifies changes. Moves system away from equilibrium.

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7
Q

What is another term for negative feedback?

A

Self-regulated

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8
Q

What are some examples of a negative feedback system?

A

House temp closed loop control system, flyball governor, water level control, cruise control

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9
Q

What is an example of positive feedback?

A

Schmitt Trigger

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10
Q

Define direct action (non-inverting)

A

Controller output signal will respond to any controller input signal change in the same direction

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11
Q

Define reverse acting (inverting)

A

Controller output signal will respond to any controller input signal change in the opposite direction

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12
Q

What is the key function/component of an open loop system?

A

Timers

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13
Q

What is the fundamental process for a flyball governor?

A

Centripetal force

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14
Q

What is the purpose of a solvent tank?

A

Provide a constant level of solvent regardless of various load behaviours.
proportional control in proportion to demand

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15
Q

What type of loop and feedback system is a solvent tank?

A

Proportional closed loop negative feedback system

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16
Q

What are the four steps in a control system/control block?

A

Process, measurement, controller/error detector, final control

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17
Q

Define a transfer function?

A

Represents the relationship between output signal of a control system and the input signal

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18
Q

Each transfer function can be described using what two terms?

A

Transfer gain K (static) and speed of response D (dynamic)

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19
Q

Digital signal is what type of control mode?

A

Discontinuous - On/Off

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20
Q

Analog signal is what type of control?

A

Continuous - proportional, integral, derivative

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21
Q

What is the first block of the block diagram?

A

Process - what needs to be controlled
Ex) water level

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22
Q

What is the second block of the block diagram?

A

Measurement Sensor - senses the controlled variable and produces a corresponding signal which is sent to the controller.
Can be called controlled variable (CV), measured variable (MV), or process variable (PV)

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23
Q

What is the third block in the block diagram?

A

Controller/Error Detector. Block receives measured variable from sensor, controller decides on what size and direction of output signal to send.

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24
Q

What is the fourth block in the block diagram?

A

Final Control - received output signal from controller, adjusts energy or material flow to or from a process.
Also called manipulated variable (MV).

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25
Q

What are some advantages of closed loop systems?

A

Faster, more consistent, and more dependable than humans. Can use more variables than humans can.

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26
Q

What are some disadvantages of closed loop systems?

A

Equipment is more complex and more expensive, installation is more difficult, equipment maintenance is challenging and requires a lot of knowledge. Possibility of ‘run away’ control system.

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27
Q

What is a run away control system?

A

The result of a faulty control system when the error signal remains at non-zero constantly.

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28
Q

How is a run away prevented?

A

Safety override control systems should be installed in critical control applications.

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29
Q

What is a proportional closed loop control system?

A

the output of one block is the input of the next block - a series of action and reaction responses makes it proportional.

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30
Q

What are some other terms for a proportional control system?

A

self-correcting system, negative feedback control system

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31
Q

What does PFD stand for?

A

Process Flow Drawings

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32
Q

What does P&ID stand for?

A

Piping and instrumentation diagram or Process and instrumentation diagram

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33
Q

What is the purpose of a P&ID?

A

Shows the ‘key components’ of equipment and the mechanical interconnections of pipes and ducts. (instruments, controllers, final controls, computers, software etc)

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34
Q

How will a primary location (normally accessible) symbol be shown?

A

A horizontal line through the shape

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35
Q

How will a field mounted symbol be shown?

A

Just the symbol, no lines through centre

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36
Q

How will an auxiliary location (normally accessible) symbol be shown?

A

Two lines horizontally through the centre

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37
Q

What is the symbol for discrete instruments?

A

Circle

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38
Q

What is the symbol for shared display, shared control?

A

Circle inside of a square

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39
Q

What is the symbol for computer function?

A

Hexagon

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40
Q

What is the symbol for a PLC?

A

Diamond inside of a square

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41
Q

How are normally inaccessible or behind the panel symbols shown?

A

The same as it’s regular symbol, but a dashed line instead of a solid line

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42
Q

What does ISA stand for?

A

International Society of Automation

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43
Q

What does ANSI stand for?

A

American National Standards Institute

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44
Q

What is the difference between ISA and ANSI?

A

ISA is the organization, ANSI is the standard

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45
Q

On a P&ID, what do the first letters of a symbol represent?

A

The measured or initiating variable, and then the modifier

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46
Q

On a P&ID, what do the succeeding letters of a symbol represent?

A

Readout or passive function, then output function, then modifier

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47
Q

What does the first letter D mean on a P&ID symbol?

A

Differential

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48
Q

What does the first letter F mean on a P&ID symbol?

A

Flow rate

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49
Q

What does the first letter I mean on a P&ID symbol?

A

Electrical current

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50
Q

What does the first letter L mean on a P&ID symbol?

A

Level

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51
Q

What does the first letter P mean on a P&ID symbol?

A

Pressure

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52
Q

What does the first letter T mean on a P&ID symbol?

A

Temperature

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53
Q

What does the second letter A mean on a P&ID symbol?

A

Alarm

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54
Q

What does the second letter C mean on a P&ID symbol?

A

Control

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55
Q

What does the second letter H mean on a P&ID symbol?

A

High

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56
Q

What does the second letter L mean on a P&ID symbol?

A

Low

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57
Q

What does the second letter I mean on a P&ID symbol?

A

Indicator

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58
Q

What does the second letter T mean on a P&ID symbol?

A

Transmit

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59
Q

What does the second letter V mean on a P&ID symbol?

A

Valve

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60
Q

What does the second letter Y mean on a P&ID symbol?

A

Convert

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61
Q

The transfer function of a control system component primarily relates to the ______ and the ______ relationship of the input and the output?

A

Size, and timing

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62
Q

Define and electrical transducer

A

A device which receives information in one form and converts it into another form

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63
Q

What are some inputs of transducers?

A

Temperature, pressure, speed, oxygen, carbon dioxide

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64
Q

What is the output of a temperature transducer?

A

Voltage/resistance signals

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65
Q

What is the output of a pressure transducer?

A

resistance signals

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66
Q

What is the output of a chemical transducer?

A

Electrical signals

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67
Q

What is the output of microphones?

A

Mechanichal vibration - Electrical signals

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68
Q

What is the output of speakers?

A

Electrical signals - mechanical vibration

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69
Q

What are the two basic types of input transducers?

A

Active, Passive

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70
Q

What is an active transducer?

A

Converts ambient physical variable monitored directly to a corresponding electrical signal.

Generates energy output caused Ryan energy force rather than an external power source to operate them.
ex) thermocouple, solar panel

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71
Q

What is a passive transducer?

A

Change their characteristic when exposed to energy but cannot generate energy on their own.
ex) strain gauge - when a weight is placed on scale the strain gauge resistance changed and the passive transducer measured the change in resistance

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72
Q

Are sensors input or output transducers?

A

Input

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73
Q

What is an example of an output transducer?

A

Speakers, actuators, LED’s. Converting electrical signals into physical changes

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74
Q

Define an electrical sensor element

A

A device that detects a quantity or energy and directly converts it into an electrical form

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75
Q

The form of an electrical sensor output can be AC, or DC, True or False?

A

True, can be both AC or DC depending on the chemical makeup and/or electromechanical makeup of the sensor itself.

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76
Q

True or False, the output of an electrical sensor element itself is too low of a level to be directly useful in control applications.

A

True

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77
Q

Define an electrical transducer

A

Device which receives information in one form and converts it into another form.

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78
Q

Is an electrical sensor element a type of electrical transducer?

A

Yes

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79
Q

Define an transmitter

A

An elaborate transducer that includes a sensor and additional components to modify sensors output to produce a sStandardized transmission signal

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80
Q

What are the standard current output signals of a transmitter?

A

4-20mA

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81
Q

What are the standard voltage output signals of a transmitter?

A

0-10V, 0-5V, 105V, -10 - 10V

82
Q

What are the standard pressure output signals of a transmitter?

A

3 - 15 psi, or 20 - 100 kPa

83
Q

How is am amplifier used in a transmitter?

A

The primary input measured in millivolts uses an amplifier to convert that very small current into a standard current signal

84
Q

What is the purpose of the filter in a transmitter?

A

stripping off or removing any electrical noise that might be present on the modified signal coming from the amplifier

85
Q

What is the main application that transducers and transmitters are usually found in?

A

Wherever measurements of physical or chemical quantities are required. Usually industrial setting for controlling diverse processes like mining, manufacturing, anything with the process of level and pressure, liquid or gas temps. etc.

86
Q

What other applications are transducers and transmitters found in other than process control?

A

Consumer products, continuous monitoring and recording, remote data acquisition, hazardous environments, biomedical

87
Q

What is the purpose of standardization of signals?

A

So that transmitters can easily interface with a wide range of industrial instruments. ex) all instruments have signal inputs of 4-20mA so a data logger can be used to log PI’s, FI’s, FT’s, etc etc

88
Q

What are the main advantages of using a current loop signal?

A
  • Less susceptible than voltage signals to electrical interface (Noise) because of low impedance input of current receivers
  • Can be transmitted over long distances without losses, opposed to voltage which will suffer voltage drop
  • Power supply is external to the transmitter and can be connected with a two wire
  • Line breakage can be detected unmistakably
89
Q

What are the main disadvantages of a current loop signal?

A

-If there is a break in any one of the series connections, the entire system will malfunction
- Length of transmission lines and number of instruments that can be driven is limited
- Two - wire current transmitters require a minimum voltage (typically 12V) to operate

90
Q

For voltage of 1-5V, what is the standard current?

A

4-20mA

91
Q

For voltage of 1-10V, what is the standard current?

A

10-50mA

92
Q

How are 4-20mA current signals connected?

A

In series

93
Q

What is the input/output relationship of a pressure transmitter?

A

Proportional, constant, ideal, linear.
Signal current to voltage transducer has a linear 4:1 conversation factor (signal scale factor)

94
Q

Define range (input and output) of a transducer

A

the stated minimum and maximum measurement values
ex) 4-20mA or 0-10V

95
Q

What is the minimum value of range in the transducer?

A

Zero value

96
Q

What is the maximum value of range in the transducer?

A

Full scale value

97
Q

What is the difference between range and span?

A

Span is the algebraic difference between the min and max value range.
ex) Range: 4-20mA, span is 16mA

98
Q

Define static transfer function

A

Input to output relationship of a device in equation form, ignoring the (dynamic) time response
ex) temperature measurements

99
Q

What is the equation of the basic device static transfer function?

A

y = mx + b
transmitter output = (output span/input span) (input meas. - input zero value) + output zero value

y = output
m = gain (slope)
x = input
b = bias (y intercept)

100
Q

Define span accuracy

A

The limit within which the output may deviate. Usually specified as a percent.
ex) +- 0.5%

101
Q

What is the formula to find span accuracy?

A

% accuracy = max deviation from actual value/theoretical span x 100%

102
Q

What are the four most common types of errors that may be found in transducer systems?

A

Bias (zero) error, Span (gain) error, linearity (gain variation), and hysteresis/dead band

103
Q

What is Bias (zero) Error?

A

Actual output value - theoretical output value. Measured at the minimum range (zero) value.
ex) 8mA - 4mA = 4mA of bias error

104
Q

What is span error (gain error)?

A

the difference in the actual output signal span compared to the theoretical span. Caused bydeviation from the ideal information transfer gain, expressed as a percent.
ex) actual span: 24mA - 4mA = 20mA
Theoretical span: 20mA - 4mA = 16mA

Error in % = 20mA - 16mA/16mA x 100% = +25%

105
Q

What is linearity error (variable gain error)

A

maximum deviation from the theoretical output after bias and span error have been removed. Expressed as a percentage of the theoretical span, also known as non-linearity.
Non linearity % = max deviation/theortetical span x 100%

ex) assume maximum deviation from theoretical is 0.5mA.
non linearity in % = 0.5mA/16mA x 100% = 3.125%

106
Q

What is hysteresis error?

A

present when the device under test gives different results when readings are taken in both the upscale and downscale directions. directional error associated with friction and backlash in mechanical devices and systems.

107
Q

What are the seven most common types of object detection sensors?

A

Photoelectric, electro-mechanical, pneumatic, magnetic, inductive, capacitive, ultrasonic

108
Q

What are the three types of photoelectric sensors?

A

Through-beam, retroreflective, and diffused

109
Q

What is an example of an electro-mechanical switch?

A

Limit switch

110
Q

What are the two types of magnetic sensors?

A

Reed switch, hall effect switch

111
Q

What is a reed switch?

A

Operates when exposed to magnetic field - there are two contacts inside that close when there is a magnetic field.
Cannot carry high currents, must be protected by fast acting fuse

112
Q

What is the hall effect?

A

Production of voltage difference across an electrical conductor that is transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current

113
Q

What is a linear hall effect sensor?

A

Provides an analog output that’s proportional to the magnetic flux density which enables precise position measurements.
ex) used widely in automotive to measure angles of mirrors

114
Q

What is a digital hall effect sensor?

A

activated by an external magnetic field. The output signal from the hall effect sensor is the function of magnetic field density around the device.

115
Q

What is an inductive sensor?

A

Device that detects metal objects without physical contact.

116
Q

What are the advantages of an inductive sensor?

A

withstand harsh environments, has a long life, easy to install, high switching rate

117
Q

What are the disadvantages of an inductive sensor?

A

Sensing rate is short, can only detect metallic targets

118
Q

What is a capacitive sensor?

A

device that detects presence of objects without making physical contact

119
Q

What is the main advantage of a capacitive sensor?

A

It can detect nearly any object/material, not just metal like an inductive sensor

120
Q

What is an ultrasonic sensor?

A

A device that measures distance based on rate and time of ultrasonic waves

121
Q

What are the three main characteristics that will affect ultrasonic sensors?

A

Density of air, temperature, humidity

122
Q

What are the six types of Linear Position Sensors?

A

linear motion potentiometer, LM variable inductor, LV variable capacitor, Linear variable differential transformer (LVDT), ultrasonic sensor, RF types of position sensors

123
Q

What is a linear motion potentiometer?

A

Device that measures an objects linear position by converting mechanical motion into electrical signal. Uses a sliding contact or wiper that moves along a resistive element changing the resistive value.

124
Q

What is a linear motion variable inductor?

A

conductive tube surrounds an inductive probe, the position of the tube or rod varies the inductance oft he probe. The resonant frequency of the oscillator is measured and the change in frequency is converted into an electrical signal.

125
Q

What is a linear motion variable capacitor?

A

uses linear motion to change the capacitor value. Set of plates or a cylinder that can move with a probe/plunger, changing the area of overlap between plates or materials.

126
Q

What is a linear variable differential transformer (LVDT)?

A

a device that converts linear motion into electrical signal. Used in aerospace, power generation, and industrial automation.
Primary winding and two secondary windings, primary winding is connected to an AC source producing flux in the air gap. The flux induces voltages in the secondary windings. Moveable iron core is placed inside the LVDT, the displacement being measured is connected to the iron core. The difference between voltages of the two secondary windings is the output voltage.

127
Q

What is an ultrasonic sensor?

A

Measures fluid levels in tanks, distances, and detects objects. A pulse of high frequency is transmitted and the time it takes for the echo to return is measured.

128
Q

What are the five types of angular position/motion sensors?

A

Potentiometer sensors, rotary motion differential transformer (RMDT), capacitive sensors, angular resolvers, encoders

129
Q

What is a potentiometer?

A

variable resistor that controls resistance in a circuit. Has a resistive element with a moving contact called a wiper that can be adjusted.

130
Q

What is the differential output formula for a RMDT?

A

Vzero = V1 - V2

131
Q

What is an optical encoder?

A

Electromechanical device, monitors the direction of rotation, position, or velocity of a rotary or linear operating mechanism.

132
Q

A Schmitt Trigger is what type of sensor?

A

Optical Encoder

133
Q

What are the four major elements of an optical encoder?

A

a light source, light sensor, optical disk, signal conditioning circuitry

134
Q

What is an absolute encoder?

A
  • Device that reads a unique code on a disc that rotates with the shaft.
  • Code is derived from light sensors on each track, a parallel output from these detectors produce highs and lows to form a 4-bit pure binary whole word that indicates the position.
  • Binary count of 0000 to 1111 is possible
  • Disk is divided into sixteen 22.5 degree sections
135
Q

What is a load cell?

A

Converts force such as tension, compression, pressure, or torque into an electrical signal.

136
Q

Define a border resistor

A

A resistor connected to the secondary side of a CT in parallel to the load, used to lower voltage on the secondary.

137
Q

What is the formula for pressure?

A

P = F/A

P - Pressure (psi)
F - Force (pounds)
A - Area (square inches)

138
Q

What are the four basic scales?

A

Gauge, absolute, differential, and vacuum

139
Q

What is a gauge pressure scale?

A

Instruments use atmospheric pressure as the reference point, can be positive or negative

140
Q

What is absolute pressure scale?

A

Instruments with absolute pressure scale are referenced to absolute zero or the complete absence of pressure. Positive values only.

141
Q

What is a differential pressure scale?

A

Used to express the difference in pressure between two measured pressures. It is determined by subtracting the lower reading for the higher reading.

142
Q

What is vacuum pressure?

A

Measured below atmospheric pressure, the zero point for vacuum pressure is referenced at the atmospheric pressure

143
Q

Which type of pressure measurement is usually more accurate?

A

Absolute pressure.

Absolute pressure = gauge pressure + atmospheric pressure

144
Q

What are three examples of primary deflection type pressure sensors?

A

Bourdon element, bellows element, diaphragm element

145
Q

What three components do deflection type pressure sensors consist of?

A

primary element, secondary element, signal conditioner

146
Q

What is the purpose of the primary element of a deflection type pressure sensor?

A

Converts the measured pressure into a proportional mechanical displacement

147
Q

What is the purpose of the secondary element of a deflection type pressure sensor?

A

Converts mechanical displacement into an electrical quantitty

148
Q

What is the purpose of the signal conditioner in a deflection type pressure sensor?

A

Converts the change of the electrical quantity into a corresponding proportional signal (for use by a controller, PLC, etc)

149
Q

What are some types of secondary elements (signals)?

A

Resistance, capacitance, inductance

150
Q

Which method of sensing is used for Open Tank Level Measurement?

A

Pressure-based liquid level sensor using a differential pressure cell. High pressure liquid is applied to only one side of the DP cell, and atmospheric pressure is applied to the other side.

151
Q

Which method of sensing is used for Closed Tank Level Measurement?

A

Pressure based liquid level sensing using a differential pressure cell. On a closed tank there is a small holding tank at the top of the tank, which is connected to the other side of the DP cell instead of atmospheric pressure. The DP cell is reading high pressure from the tank side and differential pressure from the small tank on the other side (low pressure side).

152
Q

What is the displacement float measuring method?

A

The buoyant force on a stationary float is proportional to the liquid level around the float

153
Q

What are the three other types of liquid level measuring methods?

A

Displacement float, capacitance probe, ultrasonic system

154
Q

What are the two types of ultrasonic flowmeter technologies?

A

Doppler type, transit time type

155
Q

What is a doppler flowmeter?

A

Sends an ultrasonic signal across a pipe, calcualtes the flow velocity by measuring the doppler frequency shift. pipe must be full and fluid must contain particles

156
Q

What is a transit time flowmeter?

A

Measures the difference in travel time between alternating ultrasonic beam pulses, transmitted in both the direction of flow, and the opposite direction of the flow. Time difference is used to calculate the flow rate.

157
Q

What are the three most common temperature transducers?

A

Thermocouple, resistance temperature detector, thermistor

158
Q

What is the seebeck effect?

A

The EMF that develops across two points of an electrically conducting material when there is a temperature difference between them

159
Q

What is the hot and cold junction of a thermocouple?

A

Hot - measuring point on a thermocouple
Cold - the reference point on the thermocouple

160
Q

What is a thermopile?

A

Multiple thermocouples connected in series

161
Q

What is a thermo-well?

A

Cylindrical tube that protects temperature sensors from harsh industrial conditions

162
Q

What is a resistance temperature detector (RTD)?

A

Sensor whose resistance changes as its temperature changes. REsistance increases and temp of sensor increases. RTD has a positive temperature coefficient.

163
Q

Which sensor has a negative temperature coefficient?

A

Thermistor

164
Q

Which sensor has a positive temperature coefficient?

A

RTD

165
Q

What are some advantages of the thermocouple?

A

Self powered, simple, strong, wide temp range

166
Q

What are some advantages of the RTD?

A

Most stable, most accurate, more linear than thermocouple

167
Q

What are some advantages of the thermistor?

A

High output, fast, two wire ohms

168
Q

What are some advantages of the IC sensor?

A

Most linear, highest output, inexpensive

169
Q

What is an infrared pyrometer?

A

device used to detect infrared energy emitted from an object

170
Q

How does an infrared pyrometer work?

A

Uses infrared radiation.
Total amount of energy received by infrared pyrometer is the sum of radiated energy (E), reflected energy (R), and transmitted energy (T).

Only radiated or emitted energy reflects the temperature

171
Q

Define time lag

A

From the time that the system gets the command to the time the control valve opens

172
Q

Define dead time

A

from the time the control valve opens to the time the process variable starts to change

173
Q

Define pure lag time

A

dynamic response

174
Q

What are the effects of time lags?

A

May make a feedback control system going into oscillation and being unstable. Gain of the control loop must be adjusted, reduced in order that the system maintains at the desired stability

175
Q

What are the blocks for the process level control diagram?

A

Process (tank level), Level transmitter (sensor/measurement), level controller, final control element (valve)

176
Q

What are the two main components of the controller block in the process level control?

A

Summing point, calculation unit

177
Q

What is the purpose of the controller in the process level control?

A

Detect error (set point - process value), produce an output correction in response to the error, provide the user with an adjustment for the desired value input

178
Q

What is feedback in the process level control?

A

Provides difference between the process variable and its desired value, which can take action in the appropriate direction to oppose the deviation

179
Q

What is set point?

A

The desired value of the process variable
ex) desired level of the tank

180
Q

What are the four basic modes of control

A
  • On/Off (two position) signal fully on or fully off
  • Proportional: magnitude of the output signal is directly proportional to the size of the error detected
  • Integral (reset) the output signal is in proportion to both the time duration and the size of the error detected
  • Derivative (rate) the output signal is in proportion to the rate of change of either the error or the measured process variable
181
Q

What is dead band?

A

Upper setpoint - lower set point
Also called differential gap

182
Q

What are the three continuous control modes?

A

Proportional, integral, derivative

183
Q

What is the purpose of proportional control?

A

Provide smoother control than on/off control and to reach steady state of the process

184
Q

What is an error based proportional feedback control?

A

Proportional control will always have permanent error. The permanent error or offset is necessary to keep the inflow amount of process supplies. The value of permanent error or offset depends on the outflow demand.

185
Q

What is integral control (reset)?

A
  • used in most applications to remove offset errors.
  • controller output signal will continuously change via the integral mode until the error signal again returns to zero. After every disturbance the process variable is always returned to the set point
186
Q

What is derivative control (rate)?

A

help compensate for dynamic errors in the control loop. It can reduce both the magnitude of error deviation and increase the speed of the control loop recovery.

187
Q

What is PID?

A

Proportional integral and derivative control

188
Q

What are some final control elements?

A

Solenoids, electrical motors, stepper motors, servo motor, valves

189
Q

What is the main practical use of secondary cells?

A

Used in emergency power systems because they are rechargeable

190
Q

I am a temperature detector which operates on the principle that when one junction of joined dissimilar metals is heated, an EMF proportional to the temperature difference of the junctions is produced.

Whom am I?

A

A thermocouple

191
Q

When force is applied to a strain gauge and causes it to bend, what is produced?

A

Resistance

192
Q

What is being measured at the bottom of an open tank when a pressure transducer is connected?

A

Hydrostatic head pressure

193
Q

What type of electrical output does a transducer have?

A

Voltage

194
Q

What type of electrical output does a transducer have?

A

Voltage

195
Q

Automatic control of process systems can be both open or closed loop, true or false

A

True

196
Q

The “Bias” of a PID controller output signal is normally established by the operator using the controller Manual Mode adjustment. (True/False)

A

True

197
Q

The “Bias” of a PID controller output signal is normally established by the operator using the controller Manual Mode adjustment. (True/False)

A

True

198
Q

In a Doppler ultrasonic flow meter, the difference between transmitter and receiver frequencies become __________ as the velocity of the fluid increases.

A

Greater

199
Q

Which electrical component does not have discrete characteristics

A

Thermistor

200
Q

What circuit block is designed to provide precision voltages to the other circuit blocks?

A

The reference supply

201
Q

Which component of a control system compares the desired output to the actual output?

A

The comparator

202
Q
A

Level 4 Electrical (8 decks)

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