CfE Physics – SCN 4-09 b & c

CfE Physics – SCN 4-09 b & c Electronics • Input, Process and Output • Digital Logic Gates SCN 4-09b: By contributing to investigations into the properties of a range of electronic components, I can select and use them as input and output devices in practical electronic circuits. SCN 4-09c:Using my knowledge of electronic components and switching devices, I can help to engineer an electronic system to provide a practical solution to a real-life situation. John Ogilvie High School - CfE Physics

CfE Physics SCN 4-09b Electronics Input, Process and Output John Ogilvie High School - CfE Physics

Learning Intentions: • State that an electronic system consists of three parts: input, process and output. • Identify from a block diagram the input, process and output subsystems of an electronic system. • Draw a block diagram showing the input, process and output subsystems of an electronic system. John Ogilvie High School - CfE Physics

Input, Process and Output Electronic Systems When something is made up of lots of parts which are put together to do a job, it is called a s _ _ _ _ _ .When the parts are electronic components the system is called an e _ _ _ _ _ _ _ _ _ system. system. electronic John Ogilvie High School - CfE Physics

Electronic Systems Electronic systems can do lots of jobs.The type of job will depend on the components used to make the s _ _ _ _ _ .A calculator is an example of an electronic system.Every electronic system has t _ _ _ _ main sections - called sub-systems.These are called the i _ _ _ _ , the p _ _ _ _ _ _ and the o_ _ _ _ _. system. three input, process output. John Ogilvie High School - CfE Physics

Subsystem - Input What It Does Detects some type of e _ _ _ _ _ .(for example: light, heat, sound) and changes it to e _ _ _ _ _ _ _ _ _ energy.This is then passed to the p _ _ _ _ _ _ subsystem energy. electrical process John Ogilvie High School - CfE Physics

Subsystem - Process What It Does Changes the electrical energy from the i _ _ _ _ so that the system can do its job. This is then passed on to the o _ _ _ _ _ subsystem. input output John Ogilvie High School - CfE Physics

Subsystem - Output What It Does Converts the electrical e _ _ _ _ _ from theprocess subsystem into another type of energy which can be used. For example: h _ _ _ , l _ _ _ _ ,m _ _ _ _ _ _ _ energy heat, light, movement. John Ogilvie High School - CfE Physics

Block Diagrams A block diagram is an easy way to draw a system. Instead of drawing a complicated diagram showing all the components, we draw a box or b _ _ _ _ to take the place of the i _ _ _ _ , p _ _ _ _ _ _ and o _ _ _ _ _ subsystems.Each block is labelled so that we k _ _ _ what it is. block output input, process know John Ogilvie High School - CfE Physics

Block Diagrams The block diagram for a calculator is shown above. Any subsystem can be further broken down to smaller and smaller subsystems - down to the actual components if required. John Ogilvie High School - CfE Physics

Block Diagram Examples Public Address System microphone loudspeaker amplifier John Ogilvie High School - CfE Physics

Block Diagram Examples Smoke Alarm Output Input Process buzzer John Ogilvie High School - CfE Physics

Block Diagram Examples Intruder Lamp Heat Sensor lamp John Ogilvie High School - CfE Physics

Learning Intentions • State that an input device changes some form of energy into electrical energy. • State that the microphone, thermistor, LDR and switch are all examples of input device. • State that the resistance of a thermistor changes with temperature. • State that the resistance of an LDR decreases when the light on it gets brighter. John Ogilvie High School - CfE Physics

Input and Output Devices energy Input subsystems contain a device which changes some form of e _ _ _ _ _ into electrical energy.Output subsystems contain a device which changes e _ _ _ _ _ _ _ _ _ e _ _ _ _ _ into some other form. energy electrical John Ogilvie High School - CfE Physics

Input Devices What it looks like: Device: microphone Circuit Symbol: How it Works: The inside of the microphone v_ _ _ _ _ _ _ exactly the same way as the sound waves. This makes identical electrical waves. vibrates John Ogilvie High School - CfE Physics

Input Devices What it looks like: Device: thermistor Circuit Symbol: How it Works: The resistance of the thermistor changes as the t_ _ _ _ _ _ _ _ _ _ _ changes. temperature John Ogilvie High School - CfE Physics

Input Devices What it looks like: Device: Light Dependent Resistor Circuit Symbol: How it Works: The resistance of the LDR decreases as the light level gets b_ _ _ _ _ _ _ . brighter. John Ogilvie High School - CfE Physics

Input Devices What it looks like: Device: switch Circuit Symbol: How it Works: Moving the switch from one setting to the other makes or b_ _ _ _ _ the circuit. breaks John Ogilvie High School - CfE Physics

Learning Intentions • State that an output device changes electrical energy into another form of energy. • State that a loudspeaker, buzzer, lamp, LED and electric motors are all forms of output devices. • State the energy conversions involved for a given output device. John Ogilvie High School - CfE Physics

Output Devices What it looks like: Device: loudspeaker Circuit Symbol: How it Works: Electrical energy -> Sound energy Electrical waves make vibrations inside the loudspeaker producing sound waves John Ogilvie High School - CfE Physics

Output Devices What it looks like: Device: buzzer Circuit Symbol: How it Works: Electrical energy -> Sound energy A voltage across the buzzer makes it sound. The buzzer just switches sound on or off. John Ogilvie High School - CfE Physics

Output Devices What it looks like: Device: lamp Circuit Symbol: How it Works: Electrical energy -> Light energy A voltage across the lamp makes it light. The greater the voltage, the brighter it gets. John Ogilvie High School - CfE Physics

Output Devices What it looks like: Device: Light emitting diode Circuit Symbol: How it Works: Electrical energy -> Light energy A voltage across the LED makes it light. LEDs are used to indicate when something is on or off. John Ogilvie High School - CfE Physics

Output Devices What it looks like: Device: electric motor Circuit Symbol: How it Works: Electrical energy -> Kinetic energy A voltage across the motor makes it turn. The greater the voltage, the faster it turns. John Ogilvie High School - CfE Physics

Learning Intentions • Identify from a list an appropriate input device for a given job. • Identify from a list an appropriate output device for a given job. John Ogilvie High School - CfE Physics

Examples of input and output applications Reason Device The output should be s _ _ _ _ _ waves Output of radio Loudspeaker sound Application The LDR will change resistance when the brightness changes Input of an automatic lamp L _ _ LDR The thermistor will c_ _ _ _ _ resistance when the temperature changes Input of a heating controller Thermistor change turn The motor will t_ _ _ the blades of the fan. M _ _ _ _ Motor Output of fan John Ogilvie High School - CfE Physics

CfE Physics Electronics Digital Logic Gates Scn 4-09c:Using my knowledge of electronic components and switching devices, I can help to engineer an electronic system to provide a practical solution to a real-life situation. John Ogilvie High School - CfE Physics

Learning Intentions: • State that high voltage = logic 1. • State that low voltage = logic 0. • Draw and identify symbols for 2 input AND and OR gates and a NOT gate. • State that for a NOT gate the output is the opposite of the input. • State that for an AND gate both inputs must be high for the output to be high. • State that for an OR gate either of the inputs must be high for the output to be high. John Ogilvie High School - CfE Physics

Digital Signals off ‘low’ Digital signals are either on or o _ _ .An ‘off’ signal has a zero voltage (called ‘l _ _’ ).An ‘on’ signal has a non-zero voltage(called ‘h _ _ _’ ).The ‘o _ _’ signal; low state is given the name ‘logic 0’ (most often just ‘0’). The ‘o _’ signal; high state is given the name ‘logic 1’ (most often just ‘ 1’). ‘high’ ‘off’ ‘on’ John Ogilvie High School - CfE Physics

Digital Signals 1 High voltage: Logic _ An oscilloscope can show logic states since it measures the high and low voltages. Oscilloscope trace showing a digital logicsignal which is changing from 1 to 0several times. Low voltage: Logic _ 0 John Ogilvie High School - CfE Physics

Logic Gates Digital logic gates are used to combine or change digital electronic signals. There are three basic types of logic gate called the N _ _ gate (sometimes called an i _ _ _ _ _ _ _ ), the A _ _ gate and the O _ gate. NOT inverter AND OR John Ogilvie High School - CfE Physics

The NOT gate This is the simplest gate. It has o _ _ input and o _ _ output.The output is always the opposite of the i _ _ _ _ . one one input. John Ogilvie High School - CfE Physics

NOT gate (Inverter) Symbol Logic Gate NOT Truth table How it behaves The NOT gate changes the input signal to the opposite state. Input Output High Low (0) (1) High Low (0) (1) John Ogilvie High School - CfE Physics

The AND gate The AND gate has two inputs and one output. The output of the AND gate is always at logic 0 unless both the inputs are at logic 1 when the output becomes logic 1 as well. John Ogilvie High School - CfE Physics

AND gate AND Truth table Output Input B Input A Symbol Low Low Low Logic Gate (0) (0) (0) High Low Low (0) (0) (1) How it behaves Low High Low The AND gate combines the input signals so that the output is only 1 when both inputs are 1. (0) (0) (1) High High High (1) (1) (1) John Ogilvie High School - CfE Physics

The OR gate The OR gate has two inputs and one output. The output of the OR gate is always at logic 1 unless both the inputs are at logic 0 when the output becomes logic 0 as well. John Ogilvie High School - CfE Physics

OR gate OR Truth table Output Input B Input A Symbol Low Low Low Logic Gate (0) (0) (0) High Low High (0) (1) (1) How it behaves Low High High The OR gate combines the input signals so that the output is 1 when either input is 1. (1) (0) (1) High High High (1) (1) (1) John Ogilvie High School - CfE Physics

Learning Intentions • Explain how to use logic gates for control in simple situations. John Ogilvie High School - CfE Physics

Logical solutions 1. Donnie's dad wants to be wakened if he gets up at night. Design a system to sound a buzzer if Donnie switches on his light or if he stands on a mat. (A switch is under the mat.) John Ogilvie High School - CfE Physics

Buzzer Light sensor switch Solution System Diagram John Ogilvie High School - CfE Physics

Switch Light Sensor Open Dark Closed Light high high low low How it Works high. When the light is turned on, the light sensor output is h _ _ _ . This causes the OR gate output to go high which sounds the b _ _ _ _ _ . buzzer. When the switch under the mat is pressed, it c _ _ _ _ _ _ . This makes its output h _ _ _ .This causes the OR gate output to go h _ _ _ which sounds the buzzer. closes. high. high John Ogilvie High School - CfE Physics

2. A tomato grower wants to protect his delicate plants which are in his greenhouse. Design a warning system to sound a buzzer if it gets too cold during the night (dark). John Ogilvie High School - CfE Physics

Buzzer Light sensor Temperature sensor Solution System Diagram John Ogilvie High School - CfE Physics

Light Sensor Temperature Sensor Cold Dark Warm Light high high low low How it Works high. The buzzer can only switch on when the output from the NOT gate is h _ _ _ .Therefore the output from the OR gate must be l _ _ . low. The OR gate output can only be low if b _ _ _ the inputs are low. This means it must be both d _ _ _ and c _ _ _ as well.. both dark cold John Ogilvie High School - CfE Physics

Grandad can't use the stair light switch easily since he got his walking stick. Design a system which will switch on the stair light automatically when it gets dark. There must be a manual switch as well. John Ogilvie High School - CfE Physics

Lamp Light sensor switch Solution System Diagram John Ogilvie High School - CfE Physics

Light Sensor Switch Dark Open Light Closed high high low low How it Works high When it is dark, the light sensor output is low which is changed to h _ _ _ by the NOT gate. This causes the OR gate output to go high which l _ _ _ _ _ the lamp. lights When the switch is closed, its output is high. This causes the OR gate output to go h _ _ _ which lights the lamp.. high John Ogilvie High School - CfE Physics

4. Design a system for a bathroom to switch on a fan motor when the bathroom gets so steamy, the light from the window is blocked. The fan must only come on when it is hot as well as steamy. John Ogilvie High School - CfE Physics

Motor Light sensor Temperature sensor Solution System Diagram John Ogilvie High School - CfE Physics

CfE Physics – SCN 4-09 b & c