Help me Obie Wan!

Thread Starter

Ashanti

Joined Nov 22, 2008
12
I am trying to devise a device to illustrate how a t1 circuit works. Is there an ic that will feed power, consecutively, to a series of 24 lamps? Starting at 1 stepping to 24. The speed of the steps should be variable from 1 or two per second to 24 times per second.
 

beenthere

Joined Apr 20, 2004
15,819
A couple of counter IC's like CD4029's can drive two CD4028's to give the effect you wish. Add a 555 timer for the variable frequency and some Darlington arrays to drive the LED's, and there you are.
 
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KMoffett

Joined Dec 19, 2007
2,918
beenthere,
Isn't the 4029 a binary/decimal output counter. It looks like Ashanti wants the 24 lamps to light, one at a time, in sequential order. Wouldn't three 4017 Johnson counters driven by a 555 astable work better. I assume this is the time multiplexing of 25 channels. But then, I don't know T1 from hole in a valence ring.

Ken
 
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beenthere

Joined Apr 20, 2004
15,819
Absolutely right about the chip numbers - the original of my posts is corrected.

The OP can tell us if the LED's light individually, or stay on in sequence, in which case the 4017's will be better,
 
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