Electronics 2000

Hi, i'm looking to build a circuit to fade a lighting circuit up gradually over about a 5/6 hour period from nothing to full power and then back down again. Its only 200w. any ideas?

I suspect for that sort of time you would need a proper counter - an RC based timer in't going to work due the to the leakage in the capacitor. Depending on how involved you want it to be you could look at using a microcontroller to do the timing and the dimming - Microchip have an application note for a PIC based dimmer - you'd need to modify it to add the up / down timing.

On the other had if you are looking for a ready made solution I don't know of anything off hand that would give that length of timing.

Thanks. i thought that would be the answer but thought i'd check in case there was something out there i didn't know about! i think my dad has been playing about with pic programming so i'll ask him.

I think the application note I remember is http://www.microchip.com/stellent/idcpl ... e=en011202. There is also another one that I haven't seen before at http://www.microchip.com/stellent/idcpl ... e=en025234. Hopefully these may be of some use as a starting point.

3 555 timer circuits be the way