555 delay timer

[guitardenver]

I am in need of a 555 timer that when I apply current to it, it will wait for 1min 30 sec or up to 30 min. The out put after the time needs to power a light and a relay. This is just one part of a big circuit that I built.

I Just resently learned how to use the 555 in astable to have a light flash to the designated hrz. I want this to turn on after a min or two. Could you provide a circuit and the math to determin the R's and C's for the 555 delay circuit. I am new to the electronic world so simplicity is key.

Thanks

 

[Hero999]

90 seconds should be easy, 30 minutes isn't practical for a 555.

Don't expect great accuracy, don't be surprised if your 90 second delay is anywhere in between 70s and 110s.

 

[guitardenver]

Cool could you explain how to wire the 555, and the math? And how much of a delay could I get out of a 555? Diagram would be nice but anything you want to do would be just fine.

 

[scrawny git]

I think the diagram in Fig.12 on that page should do you...

And the math is all there too, or you can just experiment with changing the values of R1 and R2 - its pretty obvious...

 

[Hero999]

555 Timer Tutorials

 

[guitardenver]

The animated one is a delay timer right?

 

[guitardenver]

Now after the dalay I want a constant output of the time ended. I do not want it to start to count down again, if it does I don't know?

 

[Hero999]

You need a monostable circuit.
**broken link removed**

 

[guitardenver]

Awsome thanks guys I can do what I want to know. But one more thing. I still need a 30min timer. The most I can get is 20 min maybe according to the math and thats with two 555's. what would be a good timer that would get up to 30min?

Also whats a good free circuite makeing software?

 

[Nigel Goodwin]

As already suggested, 30 minutes is impractical with a 555.

Using a little 8 pin PIC, and a little programming, you could get as long a delay as you wanted.

 

[Hero999]

Timer Circuits With 4060B - Electronics

 

[guitardenver]

https://www.electro-tech-online.com/attachments/3_min_timer_npn_pnp-gif.2585/


I was wondering if this circuit is good. What is the math to have it like a 3-5 sec delay so i know its working without waiting 3 min. And is the output present for the time period or does it wait for the time and then hit the relay.

 

[Hero999]

No, that's no good, it's much worse than a 555.

Did you follow the link in my previous post?

**broken link removed**

See the link for more information.