555 timing help PLEASE

Status
Not open for further replies.
I

Icadj

New Member
Hi everyone

Can someone please help with a problem.

I can just about build a 555 circuit but what I'm after is something simple what will give a short on period and a long off period. I have look on the site and unless i have missed it can find anything.

I want to replace a manually operated switch with a relay (operated by a timing device), with
an on time of about a second with an off time of (around) 30 seconds

Any simple ideas for a novice ?

Many thanks in advance
Steve
 
Last edited:
Icadj said:
Hi there ericgibbs

yes it would be repetitive

thanks
Click to expand...

hi,
The easiest way would a 555 timer set as an Astable. Do you want the output to drive a relay.?? What is your supply voltage ??

Are you asking for circuit diagram or just ideas?
 
HI
Yes I would like the output to drive a relay / supply voltage is 12.43v

Just ideas of which components to change "UNLESS" it gets complicated than I would ask for a circuit diagram

Thanks
 
The on period needs to be about a second (like you or me pressing a touch to make switch but the off period could b anywhere between 20 to 40 seconds

hope this helps
Steve
 
Icadj said:
The on period needs to be about a second (like you or me pressing a touch to make switch but the off period could b anywhere between 20 to 40 seconds

hope this helps
Steve
Click to expand...

If you have to use a push switch then the circuit is not repetitive its a one shot.??
So when you press the switch its ON for 1 second and OFF for ever, till you press again, so which is it.?

I have just drawn a repetitive circuit for you.!
 
Last edited:
Hi Eric

I want the 555 to drive a relay (circuit 1) that replaces the manual PTM switch (circuit 2) so that it becomes "automatic"
Err sorry but can not see a pic or link to your drawing

Thanks steve
 
Icadj said:
Hi Eric

I want the 555 to drive a relay (circuit 1) that replaces the manual PTM switch (circuit 2) so that it becomes "automatic"
Err sorry but can not see a pic or link to your drawing

Thanks steve
Click to expand...

hi Steve,
I didn't post the drawing as it was a repetitive circuit, here you go...


BTW: The relay contacts have been linked to +12V for test ONLY.
 

Attachments

  • AAesp01.gif
    39.6 KB · Views: 166
Last edited:
Many thanks Eric

Can you tell me what the R5 tie down resister is for
&
what ".trans 120 startup" under the 555 is?

Again many thanks steve
 
Many thanks Eric

can you give me an idea of what the off period is using the components that are show or is it trial an error for me to find of

Again thanks ,, steve
 
Last edited:
can you give me an idea of what the off period is using the components that are show or is it trial an error for me to find of
Click to expand...
You can use one of the many online 555 timer calculators.
 
Icadj said:
Many thanks Eric

Can you tell me what the R5 tie down resister is for
&
what ".trans 120 startup" under the 555 is?

Again many thanks steve
Click to expand...

Steve,
The trans startup is for my Simulator,,, the R5 as I said in my earlier post is for testing in my Sim....OK?
 
many thanks eric and everyone else for the help

Eric can you please tell me what the components in the bottom right hand corner are for

Thanks
Steve
 
Icadj said:
many thanks eric and everyone else for the help

Eric can you please tell me what the components in the bottom right hand corner are for

Thanks
Steve
Click to expand...

Hi,
The 12V is your power supply and the two capacitors are required to filter the 12V supply to the project.
 
Hi Eric
thanks for the info ,, sorry but I must ask for more help.

Have been to maplins (usless bunch OPPS) and they dont have 2n2222 in stock so can i replace it with something else, I do have quite a collection so i may have it here in the house LOL

again many thanks for your help
Steve
 
Eric
There was one other thing I wanted to ask about LEDs if i could ,, when wanting LEDs of different colours to be aprox the same brightness BUT they have different Mfd's how can I try to make sure that they give off the same amount of light ??
Did that make sense?
Steve
 

hi,
The only way I would suggest is to compare the datasheets of the LED's that you are considering.

Or buy enough in quantity so that you can match them.

Ref the 2N2222, any 200mA, 24Vce, npn should be OK
 
Last edited:
Hi Neil

Many thanks for the help "seriously you have helped loads" cheers but on the point of transistors and if i read it right would a 2n3053 be ok
The way I read it is ,, Vce 40Vdc & 700mA but will a 555 trigger the 2n3053

In your diagram c2 & c3 are 68uF ,, can you please offer a replacement as I have looked on maplins & ESR web sites and they dont list a 68uF elec CAP
There is 47 & 100uF , which would be best?

And as to the LEDs ,,, ohhhhh well trial and error and daughter dear will have to wait for her "colourfull" edge to her vanity mirror LOL

Many thanking steve
 
Last edited:
Status
Not open for further replies.

Similar threads

  • Question
Strange 555 failure
Replies
13
Views
1K
throbscottle
T
  • Question
please help
Replies
6
Views
2K
timmychangga
T
J
  • Question
Variable frequency 555 circuit
2
Replies
29
Views
2K
Papabravo
D
  • Question
Fluke 123 scopemeter not reading ANY voltage, please help
Replies
4
Views
1K
Dickos
D
F
  • Solved
Help with Serta remote circuitry please
Replies
8
Views
2K
fine2mean
F
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…