Recently, element14 was kind enough to send me a 'swag pack' which included a solderless breadboard. I wondered

what to do with it as a quick blog and then remembered a small and very simple experiment I had thought of some time

back and never tried.


My starting point was this episode of The Learning Circuit 32:  Making a FET Phase Light where Karen gave us a

circuit to sequence three LEDs. Perhaps I could extend it and make it a ring of nine sections. Would that work? We'll

see in a moment. 




Here's the circuit (after nine stages, the last output loops back to the start). I used BS170 MOSFETs simply because I had

a bag of them (2N7000 would probably work just as well). The 470nF capacitor value was a bit arbitrary, again it was just

that I had nine of them and they were in the right sort of area, along with the 470k resistor, to give a nice slow oscillation.





Here it is, built on my new breadboard:




and here it is running, to prove that it works:



Pretty flashing lights! And not a processor in sight. Season's greetings everyone.



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