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

Thank you for choosing Seeed. A couple of months ago we initiated a project to improve our documentation system. What you are looking at now is the first edition of the new documentation system. Comparing to the old one, here is the progresses that we made:

  • Replaced the old documentation system with a new one that was developed from Mkdocs, a more widely used and cooler tool to develop documentation system.
  • Integrated the documentation system with our official website, now you can go to Bazaar and other section like Forum and Community more conveniently.
  • Reviewed and rewrote documents for hundreds of products for the system’s first edition, and will continue migrate documents from old wiki to the new one.

An easy-to-use instruction is as important as the product itself. We are expecting this new system will improve your experience when using Seeed’s products. However since this is the first edition, there are still many things need to improve, if you have any suggestions or findings, you are most welcome to submit the amended version as our contributor or give us suggestions in the survey below, Please don’t forget to leave your email address so that we can reply.

Happy hacking