10 second line delay

Thread Starter

simondavidkelly

Joined Nov 12, 2009
13
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

 

debe

Joined Sep 21, 2010
1,389
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
 

Thread Starter

simondavidkelly

Joined Nov 12, 2009
13
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
 

debe

Joined Sep 21, 2010
1,389
Simon cant help with the circuit, but your beter of going for the Hysteris. Can you post the thermostat circuit? Daryl
 

debe

Joined Sep 21, 2010
1,389
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
 

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Thread Starter

simondavidkelly

Joined Nov 12, 2009
13
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 :)
 
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