10 second line delay

Discussion in 'General Electronics Chat' started by simondavidkelly, Nov 3, 2010.

  1. simondavidkelly

    Thread Starter New Member

    Nov 12, 2009
    8
    0
    Hi All,

    I'm trying to delay the start up of a power supply outputs by 10 seconds. I've got a chiller "thing" that I've put together using a peltier and some computer liquid cooling parts. Problem I have is that the thermostat flickers as it's going in and out of the temperature boundary and I want to avoid the power supply to the peltier from flickering.

    The power supply is a 200W computer supply, and I want to put the delay in the power_ok/ps_on so that when the mains comes on the power supply only goes active 10 seconds later.

    I've looked at some switching timer circuits and have put the following together. I'm pretty sure that the left side is right for a ten second delay, but I'm not sure I got the switch side right.

    Any help appreciated.

    Si

    [​IMG]
     
  2. debe

    Well-Known Member

    Sep 21, 2010
    947
    184
    Hi Si, Your aproach should be altering the thermostats cut in/out point(hysteris) the thermostat shouldnt chatter. Is the thermostat electronic? I had similar prob with an electronic thermostat. Daryl
     
  3. simondavidkelly

    Thread Starter New Member

    Nov 12, 2009
    8
    0
    It does have hysteresis settings. I'll have a look at what the settings are.

    Do you know if the above would work as a delay though? I'd like to know if I was close to what I was looking for.

    Si
     
  4. debe

    Well-Known Member

    Sep 21, 2010
    947
    184
    Simon cant help with the circuit, but your beter of going for the Hysteris. Can you post the thermostat circuit? Daryl
     
  5. simondavidkelly

    Thread Starter New Member

    Nov 12, 2009
    8
    0
    I'm using one of these
     
  6. debe

    Well-Known Member

    Sep 21, 2010
    947
    184
    This is what i used, $25 kit from Oatley Elecronics & the relay chattered untill i altered R3 to make the temp Diferential wider to about 2Deg C. The device your using did it come with instructions, Looked a fairly expensive unit. One would expect the temp diferential to be adjustable. Daryl
     
  7. simondavidkelly

    Thread Starter New Member

    Nov 12, 2009
    8
    0
    It has a booklet, if I remember where I put it, and I'll have a look through it tonight.

    I think my knowledge is a little shabby as I didn't really understand that diagram all that well. I see a copy of electronics for dummoes in my near future :)
     
Loading...