Long period AC dimmer circuit

Discussion in 'General Electronics Chat' started by boltcutter, Dec 21, 2007.

  1. boltcutter

    Thread Starter Member

    Dec 5, 2007
    19
    0
    I'm trying to build a "dawn simulator" for a bank (about 200W at 120V) of incandescent lights.

    The circuit should have the following control inputs:

    Input 1 - Momentary trigger from a timer. Begin bringing lights up to 100% power over a period of about 30 minutes.

    Input 2 - Momentary trigger from a manual pushbutton. Immediately raise power to 100%. ie, a soft power switch.

    Input 3 - Momentary trigger from a manual pushbutton. Immediately drop power to 0%.

    I know how to use a timer, but I don't know how to (safely, efficiently) build a dimmer. Has anyone seen a circuit that might steer me in the right direction, or even a product I could modify?
     
  2. lightingman

    Senior Member

    Apr 19, 2007
    374
    22
    Hi,I did post a voltage controled dimmer on here a while back (search for "2 x SCR Dimmer")....Although this used 2 thyristors, triggered by a transformer, there should be no problem converting it to use a triac triggered by an opto-isolator.The ramp timing capacitor may have to be changed for use in the USA (60Hz)....A 0 to +10 volt input, gives a 0 to 100% output.Daniel.
     
  3. boltcutter

    Thread Starter Member

    Dec 5, 2007
    19
    0
    That's a pretty impressive circuit, lightingman. I'm not competent to review it, so I'll just base my trust on noting nobody's called you on any issues to date!
     
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