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Build a super-simple blinking led / oscillator on your protoboard in under a minute!

Picture of 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!

Picture of 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!

Picture of Step 2: Put it together!
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schematic.png
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!
zhengguang4 months ago
I don't understand the T1 diagram...how does electricity pass through the transistor without the base being powered? Can someone please explain this thanks :P
RSTPhysics (author) 1 year ago
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! :)
Off the top of my head, I think the 2n2222A is the next version of the 2n2222, so should work. Cool project!
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