555 Delay circuit - badly help needed

[mahmudur.rahman]

hi....
i am trying to make a delay circuit with 555 timer that will turn on a 12V DC Load.

i designed a monostable ckt. i attached its schematic here. here when the push button is pressed the output remains high for 30 sec. i think this is a basic monostable design.

what i want is when the power will be turned on the output will remain off for 30 sec. then after 30 sec... my load will be turned on.

so, my questions are...
1. is my monostable ckt is right?
2. what i need to do to design my requirements?
3. do i need any relay or transistor?
4. do i need the push button in my required circuit?

thnx

 

[ericgibbs]

hi....
i am trying to make a delay circuit with 555 timer that will turn on a 12V DC Load.

i designed a monostable ckt. i attached its schematic here. here when the push button is pressed the output remains high for 30 sec. i think this is a basic monostable design.

what i want is when the power will be turned on the output will remain off for 30 sec. then after 30 sec... my load will be turned on.

so, my questions are...
1. is my monostable ckt is right?
2. what i need to do to design my requirements?
3. do i need any relay or transistor?
4. do i need the push button in my required circuit?

thnx

hi,
The mono timing of 30sec is OK.
Is the LED on the output the only load.
You do need a push button to trigger the mono, as you have shown it.

To get a 30sec power up delay, use another 30sec mono, to disable the first mono.

OK.??

EDIT:
This link maybe helpful
https://www.electro-tech-online.com/blogs/ericgibbs/125-simple-7555-cmos-timer-calculator-v1-2.html

 

[MrDEB]

If I understand this correctly, you have the 555 power OFF then you turn the power ON and want the circuit to stay OFF for 30 seconds?
Not hard if you have the 555 already ON before you press the pushnutton.
Another problem is the push-button needs to be de-bounced.
If you are planning on controlling 12v with the output then either a transistor or transistor/relay is needed.
more info