Purpose: To deepen theoretical understanding of current electricity concepts while improving practical electronics skills.
Materials: Cardboard support (see Mr. Jamieson’s example), transformer, wires, electrical components salvaged from old household appliances, toys, etc.
Procedure: Gather materials ahead of time. Choose five components that fit the following criteria:
1. Designed for direct current.
2. Uses small amount of power. (Total of all components cannot exceed transformer’s rated power capacity)
3. Can have V and I measured while operating.
4. Safe.
5. Different from each other.
Measure the Voltage and Current drawn by each component when it is operating as you plan it to (or hope it will) in your completed project. I will show you how to use the school equipment to do this. Calculate the resistance and power use for each component.
Design a circuit (using correct diagram symbols and rules) that has at least one parallel and at least one series component. ie. Your circuit cannot be just five parallel components. Your circuit must have a master switch to turn the whole thing on or off.
Calculate the total power of the circuit (it should be less than the rating of your transformer!), by adding the expected power use of all your components. Note that you will need to take into account the voltage each component will have available to it, which is based on your design and limited by the transformer.
Build your circuit to match your diagram and calculations. Make sure that I can measure V and I for each of your five components, while your circuit is operating.
Evaluation: Your mark will be based on the success of your circuit, the accuracy of your predictions for each component, and the quality of your written work. Your circuit will be tested to see if each component is getting the voltage and current you planned, and if the overall power use fits predictions. The calculations for each component and for the whole circuit must be shown in detail, with no naked numbers!