Page 50 - The Basics IA by ETron Circuit Labs

ETron Circuit LabsLab 25 Police SirenObjective:In this Lab you will build a Police Siren circuit that will produce a realistic police siren sound.Step 1 – Take InventoryUsing the Parts Inventory as shown on the right under the “Here’s What You’ll Need” section, place each part needed for this experiment on its corresponding drawing. Observe the schematic symbol for each part. Make sure that you have all the parts ready before you begin Step 2.Step 2 – Build the CircuitUsing the Schematic Diagram and the picture of the completed lab, build the lab experiment with the electronic components. Use the “Check Your Work Here” Box to verify that your wiring is correct, and then proceed to Step 3.Step 3 – Do ExperimentTheory:You will use the 555 Timer IC which will work as a VCO (Voltage Controlled Oscillator). When you hold down switch S1, the capacitor C2 charges causing the frequency to increase and thus the pitch to rise. When you release the pushbutton switch, capacitor C2 slowly discharges and the frequency decreases, thus the pitch goes down. You can control how high the pitch goes by holding down the pushbutton switch48