I need to know how to rotate between 3 outputs with a PBNO input using transistors. So each time I press the NO button it toggles the output between 1,2,3 then back to 1 and so forth. Any ideas???

 

You mean strictly transistors and no IC's? If yes, why is that?

 

hi,
Make a 'transistorised' shift register.

It would be far easier [and cheaper] to buy a Shift Reg ic. say a dual 4bit.

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Eric
"Good enough is Perfect"

PIC tutorials:
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an IC shift register will work. Where is a diagram of how to do this?

 

Look at the HEF4017 , 5 stage counter with 0 thru 9 outputs.

What do you plan to drive with the outputs.?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

This is a basic circuit.

Attached Images

esp03 Jul. 26.gif (4.2 KB, 23 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

I will be driving relays so I will need a darlingon array or something

 

Something like the ULN2003 might do the job.
http://www.onsemi.com/pub_link/Colla...ULN2003A-D.PDF

 

Thanks so much for the help. I think I am in the right direction now

 

I should have looked at the data sheets first, but the IOH of the counter looks a little wimpy. You may need to put pullups on the Q outputs if you go with the ULN part.

Also, after you build the circuit and if you observe erratic behavior in the switch it may be a switch bounce problem. Eric did add switch debounce for the switch, but this may cause sloping edges which might cause the CMOS part to false trigger. If this happens you might want to put a schmidt trigger device in front of the counter input.
Here is a link that discusses switch bounce.

http://www.edn.com/contents/images/196470.pdf

 

I should point out, in the RESET state, the output '0' will be High.
Pushing the pb will set '0' output low and '1' output high..etc.

If you want a totally OFF selection, move the reset link along one pin and use outputs '1 thru 3' with the reset link on output '4'.

OK.?

As Mike points out, depending upon the quality of the push switch, it may need a better debounce circuit.
The ULN2003 is CMOS compatible.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Your circuit was fine Eric, I just wanted to give a heads up just incase. I hope I did not offend

 

hi Mike,

I like to feel that all members make their posts in a spirit of cooperation rather than competition.

At the end of the day, if the OP gets the answers he needs thats all that matters to me.

In no way does it cause me a problem..

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

You are a true gentleman Mr. Gibbs, an honor to know you. Wish I could meet you in person as I am sure you would enrich my life in some way.

Thanks...

P.S. Is the Gibbs name in any relation to the Bee Gee's ? lol

 

I which you hadn't said that!

I'll now think of Eric having a high sqeaky voice every post he makes!.

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