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Your First Breadboard LED Circuit
A battery, resistor and LED make the simplest circuit.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
What you need
- Breadboard
- 3 AA cells in a holder (4.5 V)
- One red LED and a 220 ohm resistor
- Jumper wires
Steps
- Place the resistor so it bridges two rows.
- Put the LED so its long leg shares a row with the resistor's other end.
- Connect the battery positive to the free end of the resistor.
- Connect the LED's short leg to the battery negative.
With 4.5 V and a red LED, the current is (4.5 − 2) ÷ 220, about 11 mA. If nothing lights, reverse the LED. Remember that breadboard rows are connected in groups of five holes, and the long rails along the sides carry supply.
REMEMBER
Resistor first, LED the right way round.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
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