Subsystem: P1 |
Task
Title:
Touch Sensing |
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Transistor
Switch
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Introduction and Aims In this task we will now use a transistor, instead of a mechanical switch, to control an output device. We will see that the BC548B (BC108C) transistor will amplify a very small input current to make a much larger output current. This will be used to create an "electronic switch" to drive our output - in this case an LED. Subsystem Circuit and Block Diagram
Modelling the System/Circuit There are different ways to model and test circuits before components are soldered to a P.C.B.. Modelling is an important stage as it helps you spot any problems and make modifications more easily. Method 1: Breadboard Using this method, components are pushed into the interconnected holes as shown in the diagram below. The lines shown, indicate which holes are internally connected. Method 2: Computer Simulation To begin, ask your supervisor if circuit simulation software is available on your PC. This method allows you to build up your circuits quickly and cheaply in a virtual environment but will not give you hands-on experience of the components you will be using when finally soldering your P.C.B.. Method 3: Using OnTrack modelling hardware
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