jm960326
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Registered: 24th Aug 02
Location: Rob Cheshire
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Right as i said i'd have a look at making interior light dim when switched off.
Managed get it to kind off work so far, not tested on a light just on scopes displays.
Used a capacitor inline with the light. Put a resistor across the light.
This made the capacitor discharge through the resistor to the ground and hence should dim the light, (well the voltage read outs think so)
The problem with this is as you want the capacitor to supply the light after the power has been interputed, IE time delay. This also works in reverse, with the capacitor charging up in the same way. It takes the same amount of time for it to charge up as it does to discharge! But should be long enough as I got it slowly reducing for about 10s, and charging up in about that, not bad.
Anyone any thoughts of questions??
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DIGGIDY
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Registered: 15th Apr 03
Location: Bristol
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why don't you just keep the exsiting live wire to the light and run the capacitor in paralell with the live wire...?
this should instantly turn the light on and also charge the capacitor at the same time, thus no time delay. When the power is switched off the light will draw from the capacitor untill it discharges...
don't see any reason why it shouldn't work.
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jm960326
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Registered: 24th Aug 02
Location: Rob Cheshire
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True, will have a bit more of a play around on the board tomorrow.
Will see if i can get if fully working tomorrow then. Thanks for that didn't think of that one, use the capacitor as a switch circuit
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Kris TD
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Registered: 25th Mar 02
Location: Ware, Hertfordshire
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quote:
Originally posted by DIGGIDY
why don't you just keep the exsiting live wire to the light and run the capacitor in paralell with the live wire...?
this should instantly turn the light on and also charge the capacitor at the same time, thus no time delay. When the power is switched off the light will draw from the capacitor untill it discharges...
don't see any reason why it shouldn't work.
exactly what i was going to write.
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Darrylh
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Registered: 2nd Feb 03
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What uF Capacitor did you use, and what reisitor. Any diagrams?
I have just bought a delay off switch, well the componets, i will submit one i have built and tested.
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jm960326
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Registered: 24th Aug 02
Location: Rob Cheshire
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cant remember got it built on a board at uni, will check, just took handfull of compents, and plug and play almost, cant remember what the best combo was.
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Alan MacAulay
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Registered: 23rd Feb 03
Location: Irvine, Ayrshire
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I have tried this in my car with a 100uF resistor and a 500K ohm resistor, works out a a five second delay - in theory. Put it in the car resistor and capacitor in series, then in series with the bulb. It didn't work.
S21NMP off here has got it working with a kit from maplin.
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