1. 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.
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2. CfE Physics SCN 4-09b Electronics Input, Process and Output
01/04/2017
CfE Physics SCN 4-09b
Electronics
Input, Process and Output
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3. 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.
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4. 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
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5. 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.
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6. 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
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7. 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
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8. 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.
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9. 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
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10. 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.
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11. Block Diagram Examples
01/04/2017
Public Address System
microphone
loudspeaker
amplifier
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12. Block Diagram Examples
01/04/2017
Smoke Alarm
Output
Input
Process
buzzer
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13. Block Diagram Examples
01/04/2017
Intruder Lamp
Heat
Sensor
lamp
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14. 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.
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15. 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
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16. 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
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17. 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
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18. 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.
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19. 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
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20. 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.
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21. 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
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22. 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.
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23. 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.
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24. 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.
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25. 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.
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26. 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.
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27. 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
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28. 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.
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29. 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.
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30. 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’
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31. 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 _
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32. 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
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33. 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.
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34. 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)
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35. 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.
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36. 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)
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37. 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.
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38. 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)
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39. John Ogilvie High School - CfE Physics
Learning Intentions
Explain how to use logic gates for control in simple situations.
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40. 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.)
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41. Solution System Diagram
01/04/2017
Solution System Diagram
Light sensor
Buzzer
switch
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42. 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
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43. 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).
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44. John Ogilvie High School - CfE Physics
01/04/2017
Solution System Diagram
Light sensor
Buzzer
Temperature sensor
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45. 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
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46. 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.
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47. Solution System Diagram
01/04/2017
Light sensor
Lamp
switch
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48. 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
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49. 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.
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50. Solution System Diagram
01/04/2017
Light sensor
Motor
Temperature sensor
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51. 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
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52. John Ogilvie High School - CfE Physics
01/04/2017
CfE Physics
Electronics
End of Unit
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