Simple Ring Counter - Transistors

Thread Starter

iimagine

Joined Dec 20, 2010
479
I'm going to build an all transistors clock someday!
Runs well on both falstad and LTSpice, so i'm confident that it will work. Will breadboard this and see when I have the time.
What do you think?
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crutschow

Joined Mar 14, 2008
24,987
Since each LED has a 25Hz flicker rate which is near the movie frame rate of 24Hz, due to the persistence of vision it will likely look like all the LEDs are on at the same time, possibly with some flickering.
You need to slow it down if you want to see each LED on individually.
 

Thread Starter

iimagine

Joined Dec 20, 2010
479
Took me awhile to found out I have hooked up the caps wrong.!?!?
It worked! I breadboarded v4 (post# 2), set frequency to 1Hz and it flashed nicely, although I only did 2 LEDs.

Hmmm.... I'm going to try and see if i can reduce down to 1 transistor per led....prolly not possible
 

Thread Starter

iimagine

Joined Dec 20, 2010
479
If it is still available, a PUT transistor (2N6027 or 2N6028) has the two transistors in it. Digikey says they are obsolete.
Thats cheating!

I found a nice page written by Ronald Dekker about the classic neon tube ring counter. Very informative, detailed explanation. He designed and wrote about using a single transistor per tube (breakdown voltage effect). Its very interesting and nice.
https://www.dos4ever.com/ring/ring.html
 

Thread Starter

iimagine

Joined Dec 20, 2010
479
First of all, I bread boarded the circuit in post #2 again, this time with 3 LEDs just to make sure the ring is working properly, and again it works fine.
Then using Ronald Dekker's method, I came up with a design similar to post #2, wired it up and see...It works! :D
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One transistor, one LED per stage...one current limiter for all!
Only problem is I prefer to work with 5V instead of 12 :mad:
 
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