LinkIt ONE Tutorial - The Basics


What We’re Doing

Let’s build a simple circuit using a transistor, LED and a toggle switch. Light Emitting Diode (LED) transforms electrical energy into visible light. Transistor is a fundamental component in electronics which acts as a switch or a current amplifier. Here, we use a switch to ON and OFF the LED indirectly using the transistor.

Things you need

  • LinkIt One x 1
  • Bread board x 1

  • Resistors 330Ω,1kΩ x 1 each

  • 5mm LED x 1

  • Switch x 1

  • Transistor (2N3904) x 1




  • Ensure the polarity of the LED(Long lead is positive and the short lead is negative).

  • Check whether you have shorted two pins of the switch.

  • Make sure you haven’t missed the transistor connection in the circuit(A transistor is required to drive a LED).

  • Burned out an LED..?

    • This happens when you forget to connect the input resistance which acts as a current limiter to the LED.

Making it better

Now we’ve made a simple control circuit. Lets make it fascinating by just adding another component called a capacitor. A capacitor acts like a temporary charge storing device. If a capacitor is connected in parallel with the resistor which is in series with the LED it fades the LED. When the switch is turned ON the capacitor gets charged, when the switch is turned OFF the charge stored in the capacitor gets discharged slowly which makes fading OFF of the LED.

More ideas

What is the component used for growing the luminosity of the LED slowly when it is turned ON?


Help us make it better

Welcome to the new documentation system of Seeed Studio. We have made a lot of progress comparing to the old wiki system and will continue to improve it to make it more user friendly and helpful. The improvement can't be done without your kindly feedback. If you have any suggestions or findings, you are most welcome to submit the amended version as our contributor via Github or give us suggestions in the survey below, it would be more appreciated if you could leave your email so that we can reply to you. Happy Hacking!