Build a Super-simple Blinking Led / Oscillator on Your Protoboard in Under a Minute!

Introduction: Build a Super-simple Blinking Led / Oscillator on Your Protoboard in Under a Minute!

In this short tutorial I will give an example of one of the less known properties of the 2N2222 transistor.

The original idea comes from Laurier's Handy Dandy Little Circuits.

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Step 1: Step 1: Get the Components!

You will need:
1 Breadboard/Protoboard
1 Resistor  (try different values, in this tutorial I used a 510 Ohm resistor)
1 LED (Pretty much any single color, normal 20mA LED.)
1 Capacitor (Yet again, try different values, must widthstand atleast 16V. In this tutorial I used a 470µF one.)
1 2N2222 transistor  (I have not tested the 2N2222A type, so not guaranteed to work, but feel free to experiment with different types.)

And a variable powersupply! (So you can vary the voltage you power the circuit with.)

Step 2: Step 2: Put It Together!

Simply put the components in this order:

From positive on the powersupply, connect the resistor, other end of the resistor goes to the anode on the LED, cathode goes to positive pin on the capacitor, and the negative capacitor pin goes to ground.

The 2N2222 are then connected as follows: Collector to *ground* and emitter to *positive* pin on the capacitor. Leave the base unconnected, bent upwards (just for the look). :)

Step 3: Step 3: Testing and Done!

So you have connected the components to the breadboard, good! Now simply apply power, start low and slowly rise up untill it magically starts flashing! This will happen at around 10 volts.

There you have a simple but totally unstable oscillator!

1 Person Made This Project!


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5 Discussions


5 years ago

@zhengguang Pretty sure you can power the base just by pinching it between your fingertips. Not sure how it's supposed to be incorporated in this project exactly but if it didn't work as is, that would be one way to make it work I think...I'm about to try it out now, maybe I'll post my results afterwards (if I remember)


6 years ago

The 2222A does indeed work just fine. I tried this with one some time ago, and it would oscillate off a 9v transistor battery.


6 years ago on Introduction

I don't understand the T1 does electricity pass through the transistor without the base being powered? Can someone please explain this thanks :P


7 years ago on Introduction

It indeed is, just saying I doesn't have one so I can test if it indeed has the same properties as its older brother.

And thanks! :)


7 years ago on Introduction

Off the top of my head, I think the 2n2222A is the next version of the 2n2222, so should work. Cool project!