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LC TECHNOLOGY 2020/2021 - Coggle Diagram

- - - - The 555 Timer is an Intergrated Circuit( IC) used in microchip design. It is made of a series of transistor circuit(nano in size) which when activated work on the principle of logic. AND, OR, NOT . An astable circuit + Monostable circuit use the principle of the SSS timer to create two different situations: An oscillator(Astable) or a timer(Monostable)
        
        Monostable: The output switches from 0 to 1 ( off to on) for a period of time. Therefore a single output happens when the IC is triggered.
        
        Process of a 555
        timer
        
        Process of a 555 Timer
        
        Pin 1. – Ground, The ground pin connects the 555 timer to the negative (0v) supply rail.
        Pin 2. – Trigger, The negative input to comparator No 1. A negative pulse on this pin “sets” the internal Flip-flop when the voltage drops below 1/3Vcc causing the output to switch from a “LOW” to a “HIGH” state.
        Pin 3. – Output, The output pin can drive any TTL circuit and is capable of sourcing or sinking up to 200mA of current at an output voltage equal to approximately Vcc – 1.5V so small speakers, LEDs or motors can be connected directly to the output.
        Pin 4. – Reset, This pin is used to “reset” the internal Flip-flop controlling the state of the output, pin 3. This is an active-low input and is generally connected to a logic “1” level when not used to prevent any unwanted resetting of the output.
        Pin 5. – Control Voltage, This pin controls the timing of the 555 by overriding the 2/3Vcc level of the voltage divider network. By applying a voltage to this pin the width of the output signal can be varied independently of the RC timing network. When not used it is connected to ground via a 10nF capacitor to eliminate any noise.
        Pin 6. – Threshold, The positive input to comparator
        No 2. This pin is used to reset the Flip-flop when the voltage applied to it exceeds 2/3Vcc causing the output to switch from “HIGH” to “LOW” state. This pin connects directly to the RC timing circuit.
        Pin 7. – Discharge, The discharge pin is connected directly to the Collector of an internal NPN transistor which is used to “discharge” the timing capacitor to ground when the output at pin 3 switches “LOW”.
        Pin 8. – Supply +Vcc, This is the power supply pin and for general purpose TTL 555 timers is between 4.5V and 15V.
        
        Astable: The output keeps switching from 0 to 1 ( off to on) and back again constantly
      - Transistor circuits
        
        Dark sensor
        
        When the LDR(R4) is in the dark: It has high resistance. When in light: Low resistance. Therefore, for a dark sensing circuit, electrons cannot flow through R4/LDR because of high resistance. This causes electron flow through the transistor, causing it to switch on. This allows electron flow through LED , therefore the led switches on.
        
        Light Sensor
        
        When LDR is in dark: It has high resistance. When the LDR is in the light; Low resistance. Therefore , for a light sensing circuit, electrons can flow through the LDR. This causes electron flow through the transistor and through the LED. Therefore the LED lights.
        
        Hot Sensor
        
        When the Thermistor is in the hot: It has high resistance. When in cold: low resistance. Therefore, for a hot sensing circuit, electrons cannot flow through thermistor because of high resistance. This causes electron flow through transistor, causing it to switch on. This allows electron flow through LED , therefore LED switches on
        
        Time delay circuits
        
        LED 1: Lights only when capacitors reaches 0.6V because it allows electron flow into the transistor.
        LED 2: Lights due to being on outside of circuit in step 1 ( Shows power present)
        To increase charge time: Use a resistor before the capacitor to decrease the flow of electrons and increase how long you want to charge
      - Transistors
        
        Transistors can be considered as a type of switch, as can many electronic components. They are used in a variety of circuits and you will find that it is rare that a circuit developed in a school Technology Department does not contain at least one transistor. They are central to electronics and there are two main types; NPN and PNP. Most circuits tend to use NPN. There are hundreds of transistors which work at different voltages but all of them fall into these two categories.
        
        shows an NPN transistor which is often used as a type of switch.
      - Capacitors:
        
        Capacitors are components that are used to store an electrical charge and are used in timer circuits. A capacitor may be used with a resistor to produce a timer. Sometimes capacitors are used to smooth a current in a circuit as they can prevent false triggering of other components such as relays. When power is supplied to a circuit that includes a capacitor - the capacitor charges up. When power is turned off the capacitor discharges its electrical charge slowly.
        
        Process: When the circuit is switched on, the LED emits light and the capacitor charges up. When the switch is turned off the LED stills emits a light for a few seconds because the electricity stored in the capacitor is slowly discharged. When it has fully discharged its electricity the LED no longer emits light. If a resistor is introduced to the circuit the capacitor charges up more slowly but also discharges more slowly. What will happen to the light?
    - - An Op Amp is used to amplify voltage and current(or power). It takes a weak signal amplifies it, and outputs a larger power. There are 2 versions of Op amps. Inverting and Non inverting.
        
        Inverting
        
        Gain (AV) = -R2/R1 E.g. if R2 is 100 kilo-ohm and R1 is 10 kilo ohm the gin would be -100/10 = -10( Gain AV) if the input voltage is 0.5V the output voltage would be 0.5v * 10 = -5v
        
        The polarity of a signal is reversed at the output, pin six. A negative input becomes a positive output.
        
        Non-Inverting
        
        Gain(AV)= 1+(R2/R1) example: if R2 is 1000 kilo-ohm and R1 is 100kilo-ohm the gain would be 1+(1000/100)= 1+10 or Gain (Av) = 11 if the input voltage is 0.5v the output voltage would be 0.5x11= 5.5
        A signal appplied keeps its polarity at the output, pin six. A positive input remains a positive output.
        
        555 Timer as Op amp = Operation amplifiers
        
        To turn a 555 timer into an Op amp, pins 7 and 4 become power. Pins 1 and 8 are not used, Pins 2 and 3 are inputs, pin 6 is the output and pin 5 is not used ( unless joining to another 555.)
        
        Layout of a 555 timer as an op amp
        
        Basic inverting amplifer made with an op amp
    - - GENIE microcontrollers are small, programmable electronic devices that allow you to add intelligence to your project designs. The GENIE E18 project board is a versatile PIC microcontroller circuit. The 3D drawing of the circuit, shows the layout of the circuit board and the detailed circuit diagram is drawn below it.
        The circuit diagram, drawn below, shows the GENIE E18 project board. The GENIE E18 IC, is the programmable PIC microcontroller. The ULN2003 is the driver IC. This allows the use of slightly more powerful components (over 3 volts) such as motors. A simple motor will need at least 3 volts, more than the power supplied directly from the outputs of the GENIE E18. More expensive solar motors only need 1.5 volts.
        
        Circuit Diagram of Genie board
  - - - Plastics such as acrylic can be formed (shaped) in different ways. One of the most popular methods of shaping plastic materials like acrylic is to fold (bend) it on a ‘strip heater’, at different angles
        Stages of using strip heater
        1: The position of the fold is marked with a china-graph pencil. With this type of pencil line can be removed easily later.
        2: The plastic is placed across the rests, above the heating element.
        3: The strip heater is turned on and the plastic is turned over every 30 seconds - one minute. This stops the heat rising from the element damaging the surface of the plastic.
        4: When the plastic becomes flexible it is placed in a ‘jig’. The jig is made to the correct angle, 90 degrees in this case. A square section block is then pressed against the plastic to hold it in position as it cools.
        5: A second line can be drawn on the plastic with a china-graph pen, heated and folded in the same jig. The shelf is complete.
        
        Draw filing
        
        Draw filing is a technique used for producing smooth, square edges, particularly on pieces of metal. The process works by moving any type of single-cut file forwards and backwards along the length of the material’s edge.
      - Use of abrasive paper
        
        Sandpaper is produced in a range of grit sizes and is used to remove material from surfaces, either to make them smoother (for example, in wood finishing), to remove a layer of material (such as old paint), or sometimes to make the surface rougher (for example, as a preparation for gluing).
      - Finishes
        
        Some of the reasons why is a finish necessary?
        
        To protect them against the elements and resulting corrosion.
        
        To protect them against surface scratches / limited damage.
        
        To increase the aesthetic / visual appeal.
        
        To provide decoration, such as with the technique called etching.
        
        Veneer
        Veneer is a thin sheet/layer of natural wood. It is produced from a tree trunk in a number of ways. When a sheet of veneer is applied to a surface, It produces a quality, natural wood finish. Gives the illusion of an expensive natural wood, but is only 'skin' deep.
        
        Wax
        Usually supplied as a liquid or paste and is transparent or coloured. Liquid polish is useful when covering large areas, because it can be applied with a burhs. Paste wax is applied with a soft cloth and requires several coats. Results in a quality 'silk' finish. Wax should be reapplied occasionally.
        
        Varnish
        Applied to natural wood for a veriety of reasons. Offers good protection to the surface of wood. Varnish enchances the natural grain and lifts the perceived value of the product. It can also increase the lifespan of the piece. It is applied with a brush pad or spray.
- - - - CNC Router
        
        A computer numerical control router is a computer-controlled cutting machine which typically mounts a hand-held router as a spindle which is used for cutting various materials, such as wood, composites, aluminium, steel, plastics, glass, and foams
    - - 3D printing :
        A 3D printer is a computer-aided manufacturing (CAM) device that creates three-dimensional objects. Like a traditional printer, a 3D printer receives digital data from a computer as input. However, instead of printing the output on paper, a 3D printer builds a three-dimensional model out of a custom material.
      - Scrollsaw:
        A scroll saw is a small electric or pedal-operated saw used to cut intricate curves in wood, metal, or other materials. The fineness of its blade allows it to cut more delicately than a power jigsaw, and more easily than a hand coping saw or fretsaw.
      - Pillar drill:
        A pillar drill is a free standing machine that uses a motor to rotate a drill bit with variable speed range. This drill bit can be used to cut holes of different diameters into different types of material such as wood or metal.
      - Lathes
        Lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.
      - Laser cutting
        
        Laser cutting is mainly a thermal process in which a focused laser beam is used to melt material in a localised area. A co-axial gas jet is used to eject the molten material and create a kerf. A continuous cut is produced by moving the laser beam or workpiece under CNC control.
- - - - Start/End Use this shape for the first and last step of your process.
        
        Process This shape represents a typical step in your process. This is the most frequently used shape in almost every process.
        
        Decision This shape indicates a point where the outcome of a decision dictates the next step. There can be multiple outcomes, but often there are just two — yes and no.
        
        Data This shape indicates that information is coming into the process from outside, or leaving the process. This shape can also be used to represent materials and is sometimes called an Input/Output shape.
        
        Action or Process Symbol
        A box can represent a single step ("add two cups of flour"), or and entire sub-process ("make br
        ead") within a larger process.