In this lesson, we will create a closed circuit controlled by a button using Tinkercad.
Circuits usually have a button that is used to open and close the circuit. The Simulation button in Tinkercad does not qualify as a button.
This project will build on the project covered in the previous lesson. We will use the same circuit and include a button. Stop the simulation by clicking the Stop Simulation button.
Move the LED up one column to make room for the button. Place the LED in column G.
Open the components panel and find the Pushbutton.
Place the Pushbutton so that one end is in column F and the other end is on column E. In this push button switch, the diagonal terminals represent the opposite ends of the switch. This means that the current will flow from E5 to F3 when the button is pressed. More importantly, the current will not flow when the button is not pressed.
We need to have a closed circuit that includes the button. The connections from the negative terminal form the first half of our circuit as then run from the negative connection through the cathode end of the LED and into one end of the push button. We need to complete the other end of the circuit with the positive terminal connection.
Click once on the positive terminal jump wire. This will select the wire so we can remove it from the circuit. We don’t need the wire here and it’s a good idea to keep things organized. Press the delete key on your keyboard after selecting the wire.
The holes in the Breadboard only connect along rows. It is usually a good idea to keep polarized connections consistent. It helps when trying to troubleshoot problems with connections. Go to the opposite end of the Breadboard and add a jumper wire between the positive column on one end and the positive column in the other end. Change the color of the wire to red. This helps identify the jump wire as a positive terminal wire.
Complete the circuit by connecting a jumper wire from the positive terminal to the column that connects the opposite end of the button. The opposite end of this button is the diagonal opposite on the switch.
Troubleshooting The Switch
I don’t like to solve problems for my audience during presentations and I won’t solve the problem for you here either. Run the simulation and press the button. Does the LED turn on? What do you think is the reason for the LED not working as we intended? I’ll give you a hint. The anode on the LED must be connected to the positive connection of current flow.
Stop the simulation before proceeding to the solution. We cannot move components while the simulation is running. Just like you should not move components when current is flowing through them in a Breadboard.
Move the LED so the anode is connected to the push button terminal row.
After moving the LED the negative jumper wire is no longer connected to the cathode end of the LED. We don’t need to delete the jumper wire. Existing jumper wires can be moved. Click once on the jumper wire and move one end so it connects the cathode end of the LED. Jumper wires don’t have to be at right angles in order to work. A diagonal jumper wire works the same.
Run the simulation and press the push button with the mouse pointer. The LED will remain lit while the button is pressed.
This is the completed circuit.