Thursday, September 5, 2013

Single Transistor LED Flasher

How to Make a Single Transistor LED Flasher at Home

Can you imagine of making a formidable little LED flasher or blinker using just a single transistor and a couple of other passive parts.

That looks too good to be tue, however the following diagram will simply prove that it's really possible to create a legal LED blinker using just one general purpose transistor as the main component.

I came across this phenomena some eight years ago, accidentally, while trying to make a smallest possible motorcycle side indicator flasher, and was really amazed.
However, then I did have not any idea that it was happening due to the negative resistance characteristics of the transistor.

 The circuit actually exploits the negative resistance factor in transistors to produce the blinking effect.

 I'll be soon writing a comprehensive article on this and we'll see there how the concept can be modified in many different ways.

Parts List for the proposed single transistor LED flasher circuit

R1 = 2K7,
R2 = 100 Ohms,
T1 = BC 547,
C1 = 100 uF to 470 uF
LED = Any Type, any color

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