1. Engineering Science S4

2. We have been working on series circuits Simulated circuits Practical circuits Gained an understand of basic components

3. What component would we use in a circuit to make an LED come on at a certain temperature? What does LDR stand for? What happens if an LED is connected into a circuit the wrong way round?

4. We use circuits and components all the time in our daily lives. Our phones, mum/dads car, bus, Card for the canteen in school, calculators in school, Xbox/PS3 etc. All the circuits that we have made over the past week are active when they are plugged in, and remain active until we unplug them. But is that the case for EVERY circuit that we use in our lives?

5. Think about playing a computer game on your Xbox or PS3 etc What is actually happening when you are playing? You are pressing BUTTONS (push buttons) to send signals to the console.

6. Lets take an example…

7. So your about to hit a shot in Fifa…What buttons do you press? Just one? Chances are you will be pressing at least 2 buttons at the same time in order to get your player to hit an accurate shot.

8. The circuits we make only have ONE output though. The circuit is either complete or its not. This is where we need to look at “Logic Gates”

9. There are THREE main types of Logic Gate. AND gate OR gate NOT gate

10. AND gate The AND gate allows us to change two inputs, into one output. For example, in FIFA we might press “Square”(Input) and “Left”(Input) to hit a shot towards the left hand side of the goals(Output). However if we press “Square”(Input) and “Right”(Input) it will NOT hit a shot towards the left hand side of the goals(Output). This is because the game is programmed to only give the Output when Square and Left are pressed together.

11. Here is what an AND gate looks like… A=Input B=Input Q=Output

12. We can explain what happens with an AND gate by using a “Truth Table” Truth Table The numbers on the Truth Table are a way of showing that the input is “On” or “Off” 1= ON 0= OFF