In this project I demonstrate the basic principles of breadboard circuitry in preparation for more complex projects. It's important to establish a solid foundation in circuit design and electronics before jumping into bigger tasks. We'll be building three circuits, all with unique functions and components!
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What We'll Need
We'll also need a breadboard and a power supply. The convenience of a breadboard is that no soldering is required, so we can easily change or replace circuits without damaging the board or the components.
We will first demonstrate how to build a simple circuit that lights up a single Light Emitting Diode (LED). From above, we will need:
We will first demonstrate how to build a simple circuit that lights up a single Light Emitting Diode (LED). From above, we will need:
- LED
- 430 Ohm Resistor
- Jumper Wire
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Circuit 1
First, insert each leg of the LED into two slots on your breadboard. Power runs vertically through the breadboard, so ensure that the legs sit in different columns, as designated by the numbering.
Each LED has a short and a long leg, which correspond to a negative and positive electrode, respectively.
Each LED has a short and a long leg, which correspond to a negative and positive electrode, respectively.
Next, connect the short leg (negative electrode) of your LED to the negative rail at the bottom of your board using the jumper wire. Unlike the main body of your breadboard, the positive and negative rails, denoted by the blue (-) and red (+) bars, supply power horizontally down the board.
Lastly, complete the circuit by inserting one leg of the resistor into the same column as the positive electrode of your LED. The second leg of your resistor should go in the positive (red) rail. To check our circuit ensure that our components form a complete loop, starting on the positive (red) rail and ending at the negative (blue) rail.
Lastly, complete the circuit by inserting one leg of the resistor into the same column as the positive electrode of your LED. The second leg of your resistor should go in the positive (red) rail. To check our circuit ensure that our components form a complete loop, starting on the positive (red) rail and ending at the negative (blue) rail.
Now connect a power source as shown in the fritzing diagram below and watch your LED shine!
The highlighted green slots on the diagram above show where voltage is present, allowing us to see how power enters our circuit through the resistor, runs up to the positive electrode of our LED, and exits through the jumper wire.
With Circuit 1 complete, we can incorporate other components such as switches to control how our LED lights up.
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Circuit 2
From our supply list above, we will need
- 2 Push Switches
- 2 LEDs
- 2 430 Ohm Resistors
- 4 Small Jumper Wires
Circuit 2 will be very similar to Circuit 1, except we wish to utilize the push switches like on/off switches for our LED. A push switch works by controlling the current through a circuit. When pressed down, current flows normally. Otherwise, current is blocked and prevented from reaching anything past the switch.
To start building, place the negative electrode of one LED into the negative (blue) rail on your breadboard and the other leg into any slot on the main body of your board. This will be the 'starting point' of our circuit.
We extend the circuit by placing a jumper wire in the same column as LED 1. Next, we copy this set up parallel to LED 1, except placing a resistor on the positive (red) rail instead of an LED.
We extend the circuit by placing a jumper wire in the same column as LED 1. Next, we copy this set up parallel to LED 1, except placing a resistor on the positive (red) rail instead of an LED.
We could complete the circuit with a third wire between the gap; however, we want to split the circuit using our switch so that we can manually control when current flows.
Place one switch at the top of our circuit above each jumper wire with each prong of the switch in the same column as a jumper wire.
Place one switch at the top of our circuit above each jumper wire with each prong of the switch in the same column as a jumper wire.
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Copy this set up adjacent to our first circuit to use both push buttons
Once a power source is connected to your breadboard, depress either push button to light up each LED.
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Circuit 3
From our supply list above, we will need
- 1 Three Prong Switch
- 2 LEDs
- 2 xxx Ohm Resistors
- 1 Small Jumper Wire
- 3 Large Jumper Wires
In this circuit we'll use a three prong switch, also known as a Single Pole Double Throw (SPDT) switch, which allows us to direct current between two LEDs. When the slide on top of the switch is switched to the right, current flows through the right-most prong. Similarly, when the slide is pushed left, current flows through the left-most prong. The middle prong is is the ground pin, which connects to the negative (blue) rail.
The circuit diagram below shows how toggling the input (middle) pin prompts connection between either output pin.
The circuit diagram below shows how toggling the input (middle) pin prompts connection between either output pin.
Begin building by placing the 3 prong switch on the main body of your breadboard and connecting the Input Terminal (middle pin) to the negative (blue) rail with a jumper wire. Then, connect two resistors to the left and right output pins to open up the switch for connection with an LED.
Next, connect the negative electrode of each LED to one resistor, and bring the LED positive electrode to the positive (red) rail using two jumper wires. We have essentially built two distinct circuits that split off at the 3 prong switch. When the switch is directed left, the left circuit lights up, and vice-versa.
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This completes our last circuit and our review of breadboard circuitry. Time to get into some bigger projects!