varying time duration potentiometer

I'm attempting a home project and could use some help on a circuit to vary the duration from 'off to on' on a 120v AC outlet. I need to be able to adjust the time it takes to go from off to on position during a time of 5 to 30 minutes. Any ideas?

billybob5567 said:

I'm attempting a home project and could use some help on a circuit to vary the duration from 'off to on' on a 120v AC outlet. I need to be able to adjust the time it takes to go from off to on position during a time of 5 to 30 minutes. Any ideas?

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Not sure what you are getting at here? Do you mean you want to ramp the voltage up from 0 volts to 120 VAC over a period of 30 seconds? That or do you mean from power on you want a delay of 5 to 30 seconds before the mains 120 VAC goes somewhere?

Ron

From what you seem to be describing, I suspect that you're looking for a timer switch, and not a potentiometer. Here's an example...

http://lightsonrus.com/store/products/Intermatic-2%2dHour-Auto-Shut%2doff-Timer-%2d-FF2H.html

If I'm mistaken, I apologize.

I want to turn a lamp from off to on, with an increasing light intensity (based on voltage input) over a time frame of 5 to 30 minutes (not seconds). Id like to be be able to adjust the time in which this dimmer fully brightens. I don't know the best way mechanically to go about this, whether it be a servo controlled potentiometer or maybe a stepper motor? It's a long time frame... Thanks Ron

Lutron Maestro Dimmers. I have some, and they work great.

I keep thinking that this came up recently and one of the Mikes here presented a good circuit? I just can't find it. One possible solution might be to start with something like this kit from Velleman. Then just make a circuit to slowly ramp a DC level in. Maybe as simple as a pot to set time and a capacitor. Cap charges through the pot in typical RC time constant? Then switch to discharge the cap? Something like that.

Ron