UNIT TRANSISTOR Definition In electronics, a transistor is a semi-conductor device commonly used to amplify or switch electronic signals A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit A voltage or current applied to one pair of the transistor's terminals changes Fig Some types of transistor the current flowing through another pair of terminals Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal History The first patent for the field-effect transistor principle was filed in Canada by Austrian-Hungarian physicist, Julius Edgar Lilienfeld on 22 October 1925 But Lilienfeld did not publish any research articles about his devices In 1934 German physicist Dr Oskar Heil patented another field-effect transistor On 17 November 1947 John Bardeen and Walter Brattain, at AT&T Bell Labs, observed that when electrical contacts were applied to a crystal of germanium, the output power was larger than the input William Shockley saw the potential in this and worked over the next few months greatly expanding the knowledge of semiconductors and could be described as the father of the transistor, a legal papers from the Bell Labs patent show that William Shockley and Gerald Pearson had built operational versions from Lilienfeld's patents Fig Transistor in Lilienfeld’s experience The first silicon transistor was produced by Texas Instruments in 1954 This was the work of Gordon Teal, an expert in growing crystals of high purity, who had previously worked at Bell Labs The first MOS transistor actually built was by Kahng and Atalla at Bell Labs in 1960 The transistor is considered by many to be the greatest invention of the twentieth-century, and some consider it is one of the most important technological breakthroughs in human history It is the key active component in practically all modern electronics and is the fundamental building block of modern electronic devices like radio, telephone, computer etc Its importance in today's society rests on its ability to be mass produced using a highly automated process (in fabrication) that achieves astonishingly low per-transistor costs Some transistors are packaged individually but most are found in integrated circuits Although several companies each produce over a billion individually packaged (known as discrete) transistors every year, the vast majority of transistors produced are in integrated circuits (often shortened to IC, microchips or simply chips) along with diodes, resistors, capacitors and other electronic components to produce complete electronic circuits A logic gate consists of up to about twenty transistors whereas an advanced microprocessor, as of 2006, can use as many as 1.7 billion transistors (MOSFETs) "About 60 million transistors were built this year [2002], for [each] man, woman, and child on Earth." The transistor's low cost, flexibility, and reliability have made it a ubiquitous device Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery It is often easier and cheaper to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical control function Applications The bipolar junction transistor, or BJT, was the most commonly used transistor in the 1960s and 70s, after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as simple amplifiers because of their greater linearity and ease of manufacture Desirable properties of MOSFETs, such as their utility in low-power devices, usually in the CMOS configuration, allowed them to capture nearly all market share for digital circuits; more recently MOSFETs have captured most analog and power applications as well, including modern clocked analog circuits, voltage regulators, amplifiers, power transmitters, motor drivers, etc The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals This property is called gain A transistor can control its output in proportion to the input signal, that is, can act as an amplifier Or, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements The two types of transistors have slight differences in how they are used in a circuit A bipolar transistor has terminals labeled base, collector, and emitter A small current at the base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between the collector and emitter terminals For a field-effect transistor, the terminals are labeled gate, source, and drain, and a voltage at the gate can control a current between source and drain The fig represents a typical bipolar transistor in a circuit Charge will flow between emitter and collector terminals depending on the current in the base Since internally the Fig Typical circuit of transistor base and emitter connections behave like a semiconductor diode, a voltage drop develops between base and emitter while the base current exists The size of this voltage depends on the material the transistor is made from, and is referred to as VBE 3.1 Transistor as a switch Transistors are commonly used as electronic switches, for both high power applications including switched-mode power supplies and low power applications such as logic gates Using the simple transistor circuit it can be seen from the graph, from point A to point B, as the base voltage rises the base and collector current rise exponentially (the A-B segment should be curved), but the collector voltage simultaneously drops because of the collector resistor Relevant equations: IBC B A VB Fig The transistor works as a switch Following the Kirhoff laws, one can write expression: VRC = IC × RC VRC + VCE = VCC If VCE could fall to (perfect closed switch) then Ic could go no higher than VCC / RC, even with higher base voltage and current The transistor is then said to be saturated In actuality VCE drops to roughly VBE ÷ 2, rising with higher collector currents Hence, values of input voltage can be chosen such that the output is either completely off, or completely on The transistor is acting as a switch, and this type of operation is common in digital circuits where only "on" and "off" values are relevant 3.2 Transistor as an amplifier The above common emitter amplifier is designed so that a small change in voltage in (Vin) changes the small current through the base of the transistor and the transistor's current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout It is important that the operating parameters of the transistor are chosen and the circuit designed such that as far as possible the transistor operates within a linear portion of the graph, such as that shown between A and B, otherwise the output signal will suffer distortion Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing The first discrete transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive Some musical instrument amplifier manufacturers mix transistors and vacuum tubes in the same circuit, as some believe tubes have a distinctive sound Advantages The key advantages that have allowed transistors to replace their vacuum tube predecessors in most applications are - Small size and minimal weight, allowing the development of miniaturized electronic devices - Highly automated manufacturing processes, resulting in low per-unit cost - Lower possible operating voltages, making transistors suitable for small, battery-powered applications - No warm-up period for cathode heaters required after power application - Lower power dissipation and generally greater energy efficiency - Higher reliability and greater physical ruggedness - Extremely long life Some transistorized devices have been in service for more than 30 years - Complementary devices available, facilitating the design of complementary symmetry circuits, something not possible with vacuum tubes - Insensitivity to mechanical shock and vibration, thus avoiding the problem of microphonics in audio applications Disadvantages - Silicon transistors not operate at voltages higher than about 1,000 volts (SiC devices can be operated as high as 3,000 volts) In contrast, electron tubes have been developed that can be operated at tens of thousands volts - High power, high frequency operation, such as used in over-the-air television broadcasting, is better achieved in electron tubes due to improved electron mobility in a vacuum - On average, a higher degree of amplification linearity can be achieved in electron tubes as compared to equivalent solid state devices, a characteristic that may be important in high fidelity audio reproduction - Silicon transistors are much more sensitive than electron tubes to an electromagnetic pulse, such as generated by an atmospheric nuclear explosion Exercise 1: Answer the question following the text: What is a transistor? What are the transistors made of? Why can transistors provide amplification of a signal? Where are transistors used? Which type of transistor was used in 1960s-1970s What does MOSFET stand for? 7.Why is transistor used for amplifying signal? What are the terminals of BJT ? What are the terminals of FET? 10 What are the advantages of transistor compare to vacuum tube? 11.When was the first MOS transistor built? 12 How many transistors are in the advanced microprocessor in 2006? Exercise 2: Identify the statements are True or False: A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit The transistor is the fundamental building block of modern electronic devices like radio, telephone, computer and other electronic systems The transistor is considered as one of the most important technological breakthroughs in human history Transistorized mechatronic circuits couldn’t replace electromechanical devices in controlling appliances and machinery Transistors operating at high voltage not suitable for small, batterypowered applications Silicon transistors are much more sensitive than electron tubes to an electromagnetic pulse Exercise 3: Translate the text and summery in short paragraph UNIT SENSOR Definition A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument For example, a mercury thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube A thermocouple converts temperature to an output voltage which can be read by a voltmeter For accuracy, all sensors need to be calibrated against known standards Sensors are used in everyday objects such as touch-sensitive elevator buttons and lamps which dim or brighten by touching the base There are also innumerable applications for sensors of which most people are never aware Applications include cars, machines, aerospace, medicine, manu- Fig Humidity sensor facturing and robotics A sensor's sensitivity indicates how much the sensor's output changes when the measured quantity changes For instance, if the mercury in a thermometer moves cm when the temperature changes by °C, the sensitivity is cm/°C Sensors that measure very small changes must have very high sensitivities Sensors also have an impact on what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer Sensors need to be designed to have a small effect on what is measured; making the sensor smaller often improves this and may introduce other advantages Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS (Micro Electro Mechanical Systems) technology In most Fig Thermometer cases, a microsensor reaches a significantly higher speed and sensitivity compared with macroscopic approaches A good sensor obeys the following rules:  Is sensitive to the measured property  Is insensitive to any other property  Does not influence the measured property Ideal sensors are designed to be linear The output signal of such a sensor is linearly proportional to the value of the measured property The sensitivity is then defined as the ratio between output signal and measured property For example, if a sensor measures temperature and has a voltage output, the sensitivity is a constant with the unit [V/C]; this sensor is linear because the ratio is constant at all points of measurement If the sensor is not ideal, several types of deviations can be observed:  The sensitivity may in practice differ from the value specified This is called a sensitivity error, but the sensor is still linear  Since the range of the output signal is always limited, the output signal will eventually reach a minimum or maximum when the measured 10 be created from a suitable network of just NAND or just NOR gate(s) They can be built from relays or transistors, or any other technology that can create an inverter and a two-input AND or OR gate Hence the NAND and NOR gates are called the universal gates For an input of variables, there are 16 possible Boolean algebraic functions These 16 functions are enumerated below, together with their outputs for each combination Fig Logic state of two inputs of inputs variables In the 1980s, schematics were the predominant method to design both circuit boards and custom ICs known as gate arrays Today, custom ICs and the field-programmable gate array are typically designed with Hardware Description Languages (HDL) such as Verilog or VHDL The need for complex logic symbols has diminished and distinctive shape symbols are still the predominate style Two more gates are the exclusive-OR or XOR function and its inverse, exclusive-NOR or XNOR The two input Exclusive-OR is true only when the two input values are different, false if they are equal, regardless of the value If there are more than two inputs, the gate generates a true at its output if the number of trues at its input is odd In practice, these gates are built from combinations of simpler logic gates By use of De Morgan's theorem, an AND gate can be turned into an OR gate by inverting the sense 24 of the logic at its inputs and outputs This leads to a separate set of symbols with inverted inputs and the opposite core symbol These symbols can make circuit diagrams for circuits using active low signals much clearer and help to show accidental connection of an active high output to an active low input or vice-versa Fig 10 One chip with four NANDs Exercise 1: Answer the question following the text: What does logic gate perform? What relation between Boolean logic and logic gate? What is the truth table? How are the outputs created in logic gate? Which algorithms are use to reduce degree of logic gate complexity? Which components are used to build complete logic systems? What the RTL, DTL, TTL stand for? What differences between RTL, DTL and TTL? What is CMOS logic? 10 Why will fix function logic gate be replaced by PLD? 11 What are important features of FPGA? 12 What are the significant difference between logic gate and relay-and switch equivalents? 13 What major advantages are in 7400 and 4000 families? 14 Why propagation delays happen in logic system? 25 15 Why are NAND, NOR gates called universal gates? Exercise 2: Identify the statements are True or False: Logic gates are constructed using electromagnetic relays, fluidics, optics, molecules, or even mechanical elements In electronic logic, a logic level is represented only by a voltage The truth table provide the minimization procedures for designing logic system In logic system, the total system delay time is the sum of individual delay time Today, custom ICs are typically designed with VHDL An AND gate can be turned into an OR gate Exercise 3: Translate the text and summery in short paragraph 26 UNIT NANOELECTRONICS TECHNOLOGY Introduction Nanoelectronics refer to the use of nanotechnology on electronic components, especially transistors Although the term nanotechnology is generally defined as utilizing technology less than 100 nm in size, nanoelectronics often refer to transistor devices that are so small that interatomic interactions and quantum mechanical properties need to be studied extensively As a result, present transistors (such as recent Intel Core i7 processors from Intel) not fall under this category, even though these devices are manufactured under 65 nm or 45 nm technology Nanoelectronics are sometimes considered as disruptive technology because present candidates are significantly different from traditional transistors Some of these candidates include: hybrid molecular/semiconductor electronics, one dimensional nanotubes/nanowires, or advanced molecular electronics The sub-voltage and deep-sub-voltage nanoelectronics are specific and important fields of R&D, and the appearance of new ICs operating almost near theoretical limit (fundamental, technological, design methodological, architectural, algorithmic) on energy consumption per bit processing is inevitable The important case of fundamental ultimate limit for logic operation is reversible computing Although all of these hold immense promises for the future, they are still under development and will most likely not be used for manufacturing any time soon Types of nanoelctronic 27 -Nanofabrication Nanofabrication can be used to construct ultradense parallel arrays of nanowires, as an alternative to synthesizing nanowires individually For example, single electron transistors, which involve transistor operation based on a single electron Nanoelectromechanical systems also falls under this category -Nanomaterials electronics Besides being small and allowing more transistors to be packed into a single chip, the uniform and symmetrical structure of nanotubes allows a higher electron mobility (faster electron movement in the material), a higher dielectric constant (faster frequency), and a symmetrical electron/hole characteristic Also, nanoparticles can be used as quantum dots - Molecular electronics Single molecule devices are another possibility These schemes would make heavy use of molecular self-assembly, designing the device components to construct a larger structure or even a complete system on their own This can be very useful for reconfigurable computing, and may even completely replace present FPGA technology Molecular electronics is a new technology which is still in its infancy, but also brings hope for truly atomic scale electronic systems in the future One of the more promising applications of molecular electronics was proposed by the IBM researcher Ari Aviram and the theoretical chemist Mark Ratner in their 1974 and 1988 on papers Molecules for Memory, Logic and Amplification This is one of many possible ways in which a molecular level diode/transistor might be synthesized by organic chemistry A model system was proposed with a spiro carbon structure giving a molecular diode about half a nanometre across which could be 28 connected by polythiophene molecular wires Theoretical calculations showed the design to be sound in principle and there is still hope that such a system can be made to work Applications - Computers Nanoelectronics holds the promise of making computer processors more powerful than are possible with conventional semiconductor fabrication techniques A number of approaches are currently being researched, including new forms of nanolithography, as well as the use of nanomaterials such as nanowires or small molecules in place of traditional CMOS compoent Field effect transistors have been made using both semiconducting carbon nanotubes and with heterostructured semiconductor nanowires - Energy production Research nanowires and is ongoing other to use nanostructured materials with the hope to create cheaper and more efficient solar cells than are possible with conventional planar silicon Fig 11 The device transfers energy from nano-thin layers of quantum wells to nanocrystals solar cells It is believed that the invention of more efficient solar energy would have a great effect on satisfying global energy needs There is also research into energy production for devices that would operate in vivo, called bio-nano generators A bio-nano generator is a nanoscale electrochemical device, like a fuel cell or galvanic cell, but drawing power from blood glucose in a living body, much the same as how 29 the body generates energy from food To achieve the effect, an enzyme is used that is capable of stripping glucose of its electrons, freeing them for use in electrical devices The average person's body could, theoretically, generate 100 watts of electricity (about 2000 food calories per day) using a bio-nano generator However, this estimate is only true if all food was converted to electricity, and the human body needs some energy consistently, so possible power generated is likely much lower The electricity generated by such a device could power devices embedded in the body (such as pacemakers), or sugar-fed nanorobots Much of the research done on bio-nano generators is still experimental, with Panasonic's Nanotechnology Research Laboratory among those at the forefront - Medical diagnostics There is great interest in constructing nanoelectronic devices that could detect the concentrations of biomolecules in real time for use as medical diagnostics, thus falling into the category of nanomedicine A parallel line of research seeks to create nanoelectronic devices which could interact with single cells for Fig 12 Buckminsterfulleren C60 known as the buckyball, is the simplest of the carbon structure use in basic biological research These devices are called nanosensors Such miniaturization on nanoelectronics towards in vivo proteomic sensing should enable new approaches for health monitoring, surveillance, and defense technology Exercise 1: Answer the question following the text: What are nanoelectronics technology? Why are nanoelectronics called disruptive technology? 30 What candidates are included in nanoelectronic technology? Which theoretical limit of new ICs? What advantages of small size and transistors packed into single chip? Which application of molecular electronics was proposed by the IBM researcher? Which are the nano materials being researched for computer application? What is a bio-nano generator? How many watts could an average person’s body produce in theoretically? 10 What is nanomedicine? 11 What is a nanosensor? 12 Where still take experiences in bio-nano generator? 13 In bio-nano generator, from what electric power is created ? Exercise 2: Identify the statements are True or False: Nanoelectronics refer to the use of electronic components like transistors The term is generally defined as technology greater than 100 nm in size Recent Intel Core i7 processors from Intel are one type of device using nanotechnology Transistors using nanotechnology can be operated basing on a single electron Using nanotechnology makes computer processors more powerful than conventional semiconductor fabrication techniques Single molecule devices can be very useful for reconfigurable computing, and may even completely replace present FPGA technology Exercise 3: Find more information about new products that using nanotechnology Exercise 4: Translate the text and summery in short paragraph 31 UNIT AUTOMATIC CONTROL Definition Automatic control is the research area and theoretical base for mechanization and automation, employing methods from mathematics and engineering A central concept is that of the system which is to be controlled, such as a rudder, propeller or an entire ballistic missile The systems studied within automatic control are mostly the linear systems Automatic control systems are composed of three components:  Sensor(s), which measure some physical state such as temperature or liquid level  Responder(s), which may be simple electrical or mechanical systems or complex special purpose digital controllers or general purpose computers  Actuator(s), which affect a response to the sensor(s) under the command of the responder, for example, by controlling a gas flow to a burner in a heating system or electricity to a motor in a refrigerator or pump Process control is a statistics and engineering discipline that deals with architectures, mechanisms, and algorithms for controlling the output of a specific process For example, heating up the temperature in a room is a process that has the specific, desired outcome to reach and maintain a defined temperature (e.g 20°C), kept constant over time Here, the temperature is the controlled variable At the same time, it is the input variable since it is measured by a thermometer and used to decide whether to heat or not to heat The desired temperature (20°C) is the setpoint The 32 state of the heater (e.g the setting of the valve allowing hot water to flow through it) is called the manipulated variable since it is subject to control actions A commonly used control device called a programmable logic controller, or a PLC, is used to read a set of digital and analog inputs, apply a set of logic statements, and generate a set of analog and digital outputs Using the example in the previous paragraph, the room temperature would be an input to the PLC The logical statements would compare the setpoint to the input temperature and determine whether more or less heating was necessary to keep the temperature constant A PLC output would then either open or close the hot water valve, an incremental amount, depending on whether more or less hot water was needed Larger more complex systems can be controlled by a Distributed Control System (DCS) or Supervisory Control And Data Acquisition (SCADA) system In practice, process control systems can be characterized as one or more of the following forms:  Discrete – Found in many manufacturing, motion and packaging applications Robotic assembly, such as that found in automotive production, can be characterized as discrete process control Most discrete manufacturing involves the production of discrete pieces of product, such as metal stamping  Batch – Some applications require that specific quantities of raw materials be combined in specific ways for particular durations to produce an intermediate or end result One example is the production of adhesives and glues, which normally require the mixing of raw materials in a heated vessel for a period of time to form a quantity of end product Other important examples are the production of food, beverages and medicine Batch processes are generally used to produce a relatively low to 33 intermediate quantity of product per year (a few pounds to millions of pounds)  Continuous – Often, a physical system is represented though variables that are smooth and uninterrupted in time The control of the water temperature in a heating jacket, for example, is an example of continuous process control Some important continuous processes are the production of fuels, chemicals and plastics Continuous processes, in manufacturing, are used to produce very large quantities of product per year (millions to billions of pounds) Some types of automatic control system A thermostat is a simple example for a closed control loop: It constantly measures the current temperature and controls the heater's valve setting to increase or decrease the room temperature according to the user-defined setting A simple method switches the heater either completely on, or completely off, and an overshoot and undershoot of the controlled temperature must be expected A more expensive method varies the amount of heat provided by the heater depending on the difference between the required temperature (the "setpoint") and the actual temperature This minimizes over/undershoot An anti-lock braking system (ABS): is a more complex example, consisting of multiple inputs, conditions and outputs The PID controller: involving three separate parameters: the proportional, the integral and derivative values The proportional value determines the reaction to the current error, the integral value determines the reaction based on the sum of recent errors, and the derivative value determines the reaction based on the rate at which the error has been changing The weighted sum of these three actions is used to adjust the process via a 34 control element such as the position of a control valve or the power supply of a heating element By tuning the three constants in the PID controller algorithm, the controller can provide control action designed for specific process requirements The response of the controller can be described in terms of the responsiveness of the controller to an error, the degree to which the controller overshoots the setpoint and the degree of system oscillation Note that the use of the PID algorithm for control does not guarantee optimal control of the system or system stability Some applications may require using only one or two modes to provide the appropriate system control This is achieved by setting the gain of undesired control outputs to zero A PID controller will be called a PI, PD, P or I controller in the absence of the respective control actions PI controllers are particularly common, since derivative action is very sensitive to measurement noise, and the absence of an integral value may prevent the system from reaching its target value due to the control action Note: Due to the diversity of the field of control theory and application, many naming conventions for the relevant variables are in common use Control loop basics A familiar example of a control loop is the action taken to keep one's shower water at the ideal temperature, which typically involves the mixing of two process streams, cold and hot water The person feels the water to estimate its temperature Based on this measurement they perform a control action: use the cold water tap to adjust the process The person would repeat this input-output control loop, adjusting the hot water flow until the process temperature stabilized at the desired value 35 Feeling the water temperature is taking a measurement of the process value or process variable (PV) The desired temperature is called the setpoint (SP) The output from the controller and input to the process (the tap position) is called the manipulated variable (MV) The difference between the measurement and the setpoint is the error (e), too hot or too cold and by how much As a controller, one decides roughly how much to change the tap position (MV) after one determines the temperature (PV), and therefore the error This first estimate is the equivalent of the proportional action of a PID controller The integral action of a PID controller can be thought of as gradually adjusting the temperature when it is almost right Derivative action can be thought of as noticing the water temperature is getting hotter or colder, and how fast, anticipating further change and tempering adjustments for a soft landing at the desired temperature (SP) Making a change that is too large when the error is small is equivalent to a high gain controller and will lead to overshoot If the controller were to repeatedly make changes that were too large and repeatedly overshoot the target, the output would oscillate around the setpoint in either a constant, growing, or decaying sinusoid If the oscillations increase with time then the system is unstable, whereas if they decay the system is stable If the oscillations remain at a constant magnitude the system is marginally stable A human would not this because we are adaptive controllers, learning from the process history, but PID controllers not have the ability to learn and must be set up correctly Selecting the correct gains for effective control is known as tuning the controller If a controller starts from a stable state at zero error (PV = SP), then further changes by the controller will be in response to changes in other 36 measured or unmeasured inputs to the process that impact on the process, and hence on the PV Variables that impact on the process other than the MV are known as disturbances Generally controllers are used to reject disturbances and/or implement setpoint changes Changes in feed water temperature constitute a disturbance to the shower process In theory, a controller can be used to control any process which has a measurable output (PV), a known ideal value for that output (SP) and an input to the process (MV) that will affect the relevant PV Controllers are used in industry to regulate temperature, pressure, flow rate, chemical composition, speed and practically every other variable for which a measurement exists Automobile cruise control is an example of a process which utilizes automated control Due to their long history, simplicity well grounded theory and simple setup and maintenance requirements, PID controllers are the controllers of choice for many of these applications Exercise 1: Answer the question following the text: What is an automatic control? What components are in the control system? What is the Process control? Which theoretical limit of new ICs? What advantages of small size and transistor packed into single chip? What are the parameters of PID controller? What are the weighted sums of those three parameters used to? What is process variable (PV)? What is it used for? What is set point values (SP)? What is it used for? 10 What is manipulated variable (MV)? What is it used for? 37 Exercise 2: Identify the statements are True or False: Automatic control systems are composed of three components: Sensor, responder, actuator In automatic control systems, responder component must be mechanical systems Actuator affects a response to the sensor under the command of the responder A PID controller can be called a PI, PD, P or I controller The variables that impact on the process other than the manipulated variables are known as disturbances A commonly used control device is called a programmable logic controller (PLC) Exercise 3: Design a simple automatic control system and describe how it works 38