# John Ogilvie High School - CfE Physics

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John Ogilvie High School - CfE Physics
01/04/2017 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
01/04/2017 CfE Physics SCN 4-09b Electronics Input, Process and Output John Ogilvie High School - CfE Physics

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

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

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

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

John Ogilvie High School - CfE Physics
Subsystem - Output What It Does Converts the electrical e _ _ _ _ _ from the process 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

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 input, process output know John Ogilvie High School - CfE Physics

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
01/04/2017 Public Address System microphone loudspeaker amplifier John Ogilvie High School - CfE Physics

Block Diagram Examples
01/04/2017 Smoke Alarm Output Input Process buzzer John Ogilvie High School - CfE Physics

Block Diagram Examples
01/04/2017 Intruder Lamp Heat Sensor lamp John Ogilvie High School - CfE Physics

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
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 energy John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
Input Devices Device: microphone What it looks like: 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

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

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

John Ogilvie High School - CfE Physics
Input Devices Device: switch What it looks like: 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

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

John Ogilvie High School - CfE Physics
Output Devices Device: loudspeaker What it looks like: 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

John Ogilvie High School - CfE Physics
Output Devices Device: buzzer What it looks like: 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

John Ogilvie High School - CfE Physics
Output Devices Device: lamp What it looks like: 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

John Ogilvie High School - CfE Physics
Output Devices Device: Light emitting diode What it looks like: 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

John Ogilvie High School - CfE Physics
Output Devices Device: electric motor What it looks like: 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

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

John Ogilvie High School - CfE Physics
01/04/2017 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

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

John Ogilvie High School - CfE Physics
Digital Signals 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’). off ‘low’ ‘high’ ‘off’ ‘on’ John Ogilvie High School - CfE Physics

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

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

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

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

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

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

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

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

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

John Ogilvie High School - CfE Physics
01/04/2017 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

Solution System Diagram
01/04/2017 Solution System Diagram Light sensor Buzzer switch John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
How it Works 01/04/2017 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 _ _ _ _ _ . Light Sensor Dark Light low high high. 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. Switch Open Closed low high closes. high. high John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
01/04/2017 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

John Ogilvie High School - CfE Physics
01/04/2017 Solution System Diagram Light sensor Buzzer Temperature sensor John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
How it Works 01/04/2017 Light Sensor Dark Light low 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 _ _ . high. low. Temperature Sensor Cold Warm low high 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

John Ogilvie High School - CfE Physics
01/04/2017 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

Solution System Diagram
01/04/2017 Light sensor Lamp switch John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
How it Works 01/04/2017 Light Sensor Dark Light low 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. high lights Switch Open Closed low high 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

John Ogilvie High School - CfE Physics
01/04/2017 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

Solution System Diagram
01/04/2017 Light sensor Motor Temperature sensor John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
How it Works 01/04/2017 When it is steamy, it gets darker, the light sensor output is l _ _ which is changed to high by the N _ _ gate. When it gets too h _ _ the output from the temperature sensor is h _ _ _ . Light Sensor Dark Light low high low NOT hot high. Temperature sensor Cold Warm low high Only when it is hot and steamy at the s _ _ _ time will both inputs of the AND gate be high to make the output high to t _ _ _ the motor. . same turn John Ogilvie High School - CfE Physics

John Ogilvie High School - CfE Physics
01/04/2017 CfE Physics Electronics End of Unit John Ogilvie High School - CfE Physics