STEM/Robotics/ATL Tinkering Curriculum | Level 1 | Experiment 2 | LED Blinking Circuit Using Switch
To teach students how to control an LED circuit using a switch. This experiment builds on the previous LED circuit by introducing a switch to manually control the flow of current, thereby turning the LED on and off.
Materials Required:
Breadboard
LED (Light Emitting Diode)
220-ohm resistor
Jumper wires
9V Battery with battery clip
Push button (switch)
Connecting wires
Circuit Diagram:
LED: Place the LED on the breadboard with its longer leg (anode) connected to a free row.
Resistor: Connect one end of the 220-ohm resistor to the same row where the LED anode is connected. The other end of the resistor should be connected to another row on the breadboard.
Switch: Place the switch on the breadboard with one terminal connected to the row where the resistor is connected and the other terminal connected to a separate row.
Power Connections:
Positive Terminal: Connect the positive terminal of the 9V battery (using the battery clip) to the row where the other terminal of the switch is connected.
Negative Terminal: Connect the negative terminal of the battery to the row where the shorter leg (cathode) of the LED is connected.
Steps to Construct:
Place the LED on the Breadboard: Insert the legs of the LED into two separate rows of the breadboard. The longer leg (anode) is the positive terminal, and the shorter leg (cathode) is the negative terminal.
Connect the Resistor: Insert one leg of the resistor into the same row as the anode (longer leg) of the LED. The other leg of the resistor should go into a different row.
Place the Switch: Insert the switch into the breadboard so that it bridges two rows. Connect one side of the switch to the row where the resistor is connected and the other side to a separate row.
Make the Power Connections:
Connect the positive terminal of the 9V battery (using the battery clip) to the row where the switch is connected.
Connect the negative terminal of the battery to the row where the cathode (shorter leg) of the LED is connected.
Working Principle:
When the switch is pressed, it closes the circuit, allowing current to flow from the positive terminal of the battery through the resistor to the anode of the LED, causing it to light up. When the switch is released, the circuit is opened, and the LED turns off. The resistor ensures the current is regulated to protect the LED from burning out.
Expected Outcome:
The LED should turn on when the switch is pressed and turn off when the switch is released, demonstrating the control of current flow using a switch.
Safety Tips:
Ensure the correct polarity of the LED and battery to avoid damage to the components.
Double-check connections to prevent short circuits.