There are many different types of transistors, and the Bipolar Junction Transistor (BJT) is one of the most popular styles. It’s also fairly straightforward to use and is a good option for anyone new to working with transistors. A BJT transistor works by receiving a small electrical current and converting it into a much larger current. [2] X Research source
These 3 pins each serve a different function, so it’s important to correctly identify them.
This may take some delicate work since each of the breadboard holes is only about 1⁄32 inch (0. 79 mm) across. A breadboard is a roughly 10 in × 6 in (25 cm × 15 cm) piece of plastic with electrical wiring running between the individual holes. It’s commonly used in electrical experiments with transistors since electrical power will run between any metal elements connected to the breadboard.
Insert the first resistor on the upper-right hand side of the transistor within 2-3 holes of those the transistor is in. Then, place the second resistor on the lower-left side of the transistor, also within 2-3 holes of the transistor’s location. Resistors help slow down and re-direct the flow of electric current. They’re used in simple circuits to prevent the wiring and LED bulb from overheating. Resistors look like a 2 in (5. 1 cm) piece of wire with a 1 in (2. 5 cm) plastic tube wrapped around the middle. [6] X Research source
When you’re connecting the LED, always connect the anode to the circuit’s positive side. If you mistakenly connect the anode to the circuit’s negative side, the circuit won’t work and the LED won’t light up. LED bulbs burn brightly when powered with only a small amount of electric current.
To connect the cathode lead to the transistor pin, simply twist the 2 wires together under the breadboard. Make 2-3 twists to ensure that electricity can flow between the wires.
Make the connection sturdy by bending the resistor wires 2-3 times around the wires you connect them to.
If you don’t have wire cutters, purchase a pair at a local hardware or electronic-supply store.
Identify the negative power edge of the breadboard by visually inspecting it. Both of the 2 long edges of the breadboard will have both a negative and positive rail. The negative rail will always be accompanied by a “–” sign and will be blue or black. [12] X Trustworthy Source Science Buddies Expert-sourced database of science projects, explanations, and educational material Go to source
Choose holes in the same row so that the 2 long wires are parallel to one another. Due to the wire segments length, the 2 ends of each segment will be inserted roughly 25 holes apart.
If the wires are too short or too stiff to bend with your fingers, use a pair of needle-nose pliers to bend the wires.
This will allow power from the battery to get to the LED, once you’ve connected the battery.
The 9-volt adapter comprises a rubber head with 2 receivers to snap on the + and – ports of the battery. Notice that 2 wires emerge from the head: 1 positive (red) and 1 negative (blue).
Try experimenting with different types of touch: light, heavy, etc. Depending on how much pressure you put on the wires, you’ll notice that the LED illuminates more or less brightly.
