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Download Night Light Name : Class : My Learning Outcomes How did you feel
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Night Light Name : Class _______________________________ : ________________________________ My Learning Outcomes How did you feel that you achieved your learning Intention? Fully (3) Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Partially (2) Not At All (1) Night Light Situation When told to switch off my light at night I sometimes wish that I could have the light on for a little while longer. Light at night helps me get to sleep and comforts me in the dark. Design Brief Design and make a ______________________ Specification Now make a list of some of the things that a good Night Light will have or will do. This is called a specification. Function (What must it do ?) _______________________________________ _______________________________________ Appearance (What should it look like ?) _______________________________________ _______________________________________ Quality (How well should it be made ?) _______________________________________ _______________________________________ Safety (How safe is it ? ) _______________________________________ _______________________________________ Cost ( What is a reasonable price ?) _______________________________________ _______________________________________ Electronic Circuit Symbols In Technology and Design we can draw special pictures to show the different things in an electronic circuit. These are called circuit symbols. Some of these symbols are shown below. Symbol Name Battery Variable Resistor Resistor Switch LED Motor Buzzer Transistor Light Dependant Resistor Picture Electronic Circuit Symbols – Work Sheet Silly Sammy does not know what each of the circuit symbols mean. Can you help him match the symbols to the electronic components. Symbol Name Battery Variable Resistor Resistor Switch LED Motor Buzzer Transistor Light Dependant Resistor Picture Match The Components Shown below Electronic Building Blocks Electronic components are the building blocks that go together to build an electronic circuit. You can use these building blocks to design and build the circuit you want. A circuit should have three main blocks : an Input, a Control and an Output. This can be seen as a block diagram like the one below. INPUT CONTROL OUTPUT INPUT: The INPUT part of the circuit senses and reacts to changes in its surroundings. For example, changes in Temperature, the level of Light or Moisture in the surrounding environment. CONTROL: The CONTROL part of the circuit reacts to changes in the Input and tells the Output part what to do. Eg: It controls the Output. OUTPUT: The Output part of the circuit produces Sound, Light, Heat or Movement. The Output part is switched on and off by the Control. Input components are really variable resistors. Changes in their resistance can be detected by the control part of the circuit. Control Components detect changes in the input and react to control the Output. Output Components- Circuits are used to control Outputs. Outputs can be Light, Sound, Heat or Movement. INPUT COMPONENTS Light Sensor Temperature Sensor Symbol Moisture Sensor Symbol Symbol CONTROL COMPONENT Transistor symbol OUTPUT COMPONENTS Light / Bulb Symbol Sound / Buzzer Movement / Motor Symbol Symbol LED Symbol Speaker Symbol Transistors What are they? A Transistor is a very useful component for controlling a circuit. It can be used to link the Input to the Output. For example a Transistor could be used to link a light sensor (Input Component) to a lamp (Output Component). A Transistor has three legs. Each has a name. The leg closest to and left of the tab is called the emitter. The leg next to the emitter is called the base. The third leg is called the collector. The three legs must be connected the correct way in a circuit or the Transistor will not work. A Transistor is a kind of electronic switch. If electricity flows into the base leg the transistor will switch on the outputs. Transistors How they work? The activity on this sheet demonstrates how a transistor works. Draw the Transistor circuit below using Livewire. 1. When the switch is open is the LED on or off ? ________ 2. When the switch is closed is the LED on or off ? _______ 3. Into which leg of the Transistor is the switch controlling the electric current ? ____________ 4. What is the purpose of the 1K Resistor in the circuit ? _____________________________________________ The LED will only be lit if there is a complete circuit. To have a complete circuit an electric current must be able to pass through the Transistor from the Collector to the Emitter. This can only happen if there is a voltage at the base of the Transistor. Resistors A resistor is a device which reduces the current flowing in a circuit. The greater the resistance the smaller the current. Electrical resistance is measured in ohms and the symbol for ohms is (Ω). Think of water flowing in a hosepipe, if someone stands on the tube the flow of water is reduced or even stopped. The more the tube is squashed the greater the resistance and the smaller the flow of water. Place Resistors X, Y and Z in the circuit shown below and observe the bulb. 1. 2. 3. 4. With which resistor was the bulb brightest? With which resistor was the bulb dimmest? Which resistor had the most resistance? Which resistor had the least resistance? Resistors have four coloured bands which tell you the value of each resistor and how accurate that value is. Below you can see what a resistor actually looks like. Resistors As you know, resistors have different values. We can work out the value of each resistor by looking at the four coloured bands that each resistor has and by using a resistor table. Resistor Table 1st Band 2nd Band 3rd Band Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Grey 8 White 9 Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Grey 8 White 9 Black No zero’s Brown 0 Red 00 Orange 000 Yellow 0000 Green 00000 Blue 000000 By using the resistor table above we can work out the value of the resistor shown below. Orange Orange Brown If we look at the first colour of the resistor and also look at the first band in the resistor table you will see that the number beside Orange is 3. If we look at the second band in the resistor table and look at the second colour which is also Orange you will see that the number beside Orange is also 3. Now by looking at the third band on the resistor you will see that it is Brown. The third band on the resistor table tells us how many Zero’s to add. In this case we add 1 zero so our answer is 330 Ohms or 330 Ω Resistor Worksheet Use your resistor table to work out the values of the resistors shown below. Red Red Brown ___________ Brown Red Black _____________ Blue Brown Orange _____________ Red Red Red _____________ Using the resistor table work out the colours of the resistors shown below: 330 ohms __________________ 27 ohms __________________ 1000 ohms _____________________ 67000 ohms _____________________ Plastics Plastics are a man-made (synthetic) material. They are made from crude oil. There are many different types of plastic which have many different properties. They can be rigid, flexible, hard, or soft, opaque or transparent. However, all plastics can be divided into two groups depending on how well they react to heat. Thermosetting Plastics: These plastics are resistant to heat and once formed into a shape they can not be reshaped. Items which are used near heat such as saucepan handles or electrical fittings are usually made from thermosetting plastics. Thermoplastics: These plastics can be reshaped by heat. Once shaped, they can be heated and reshaped again and again. These plastics can not be used in situations where they will get hot or would change shape. Examples include, Acrylic & Rigid Polystyrene Questions: 1. What is the name of the plastic you used to make your project? __________________________________________ 2. What properties does this plastic have which makes it suitable for this project? __________________________________________ 3. Is this plastic a Thermoplastic or Thermosetting Plastic? __________________________________________ 4. What machine did you use to shape your Plastic? __________________________________________ Soldering Soldering makes a permanent joint between two pieces of metal. It can be used on most metals but not on aluminium. Solder is an alloy made up from a mixture of tin and lead. A substance called flux is used with solder. Flux cleans the surfaces to be joined. Multicore solder is hollow and has flux inside it. Solder is melted using a soldering iron. The soldering iron is tinned by putting a small amount of solder onto it. It is very important that all work being soldered is properly heated in order to get a good joint which makes good electrical contact. If a component is not properly heated, molten solder may flow around it but not actually bond onto it. This is known as a dry joint and electricity may not pass through it. Some components such as LED’s can be easily damaged if they get too hot. Printed Circuit Boards Printed circuit boards (PCB’s) are plastic with copper lines. The components are soldered not the copper. 1. Solder is an alloy - from what two metals is it composed? ________________________________________________ 2. What type of materials can be joined by soldering? ________________________________________________ 3. When soldering why is it important to heat all the components properly? ________________________________________________ 4. The PCB onto which you soldered your components is made from two different materials. What are they and which is the insulator and which is the conductor? ____________________________ Output Light Emitting Diode (LED) LED stands for Light Emitting Diode. An LED has two legs, positive and negative. LED’s come in a variety of shapes and sizes. They can also be found in a range of colours, usually red, green, yellow and amber. LED’s are used a lot in electronics because they are very reliable and cheap to run, as they use very little current. Care must be taken when soldering. The legs must not get too hot or the LED will blow. Care must also be taken that the legs of LED do not touch as this will prevent the circuit from working. Circuit Symbol Negative leg Positive Leg There are two ways to identify the negative leg of an LED. The short leg is negative, and the leg closest to the flat rim is also negative. Products with LED’s Evaluation Now that you have completed your Night Light it is important that you take time to evaluate it. To do this you will have to decide how well it turned out, what worked well, what did not and what changes you would make if you were doing it again. To decide how well it turned out you must go back to your original specification at the start of the project and decide if you managed to meet the aims set out there. Specification It should ; Light up in the dark Be colourful and appealing Be strong and well finished e.g. Finished to a high standard Be safe to use – (All electrical components concealed) Be user friendly – (Easy to use and understand) Be made for under £3.00 What do others think ? In order to get a good evaluation of your product it is often a good idea to get some other members of your class to give you their opinion of your work. It is important that your classmates evaluate your work honestly and fairly. To help you evaluate your work please complete the evaluation sheet provided, and pass it on to three of your classmates for their opinion. Night Light Evaluation: For each point of your specification score your project out of ten. Use the guidelines below. 10 – 9 8–7 6–5 4–3 2–1 Excellent standard with no faults Very good work with only a few faults Average work with some mistakes Work of a poor standard with many faults Very poor, incomplete work. Specification My Score Pupil No. 1 Pupil No. 2 Pupil No. 3 Light up in the dark Colourful & Attractive Strong & Good quality finish Safe to use User Friendly Made for under £3.00 Total Score If you were to make this project again what would you do differently? (Change the design, the materials, the colours) Give a reason for your answer ? _________________________________________________ _________________________________________________ _________________________________________________ ________________________________________________ Assessment: Name: ____________ AFL / Feedback Night Light Vacuum Forming and Cutting Rigid Polystyrene V.Form: Cutting: 1 2 3 4 5 6 7 8 9 10 O O O O O O O O O O O O O O O O O O O O Finishing Edge of Rigid Polystyrene Finish: O O O O O O O O O O Drilling Rigid Polystyrene Drilling O Soldering O O O O O O O O O Soldering O Components Soldering O PCB O O O O O O O O O O O O O O O O O O O O O O O O O O O Assembly Assembly of Project O Scale: 1 – 10 With 1 = Very Poor & 10 = Excellent Total: 70