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Dome light dimmer for cars

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synergy

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Hi guys,

Any idea where can I get the schematics for the dome light dimmer to be used in car. Which means that when I open the door, the light will light up and when closed, the light will slower dim and off.

cheers!
 
The first link shows all the door switches and a selector switch to determine which means , if any , to turn on the light. The text below explains it all. The second link simplifies it all. To answer your question, yes the light will be on full brightness as long as door is open.
 
The first circuit has transistors connected together without any current-limiting resistors. Smoking transistors?
 
The first circuit has transistors connected together without any current-limiting resistors. Smoking transistors?

Speaking of smoking, be careful that you don't connect the switch and the lamp in the second circuit in parallel by accident.

Now I just need to find the schematic for my power supply kit. My shed still smells like BBQ'd resistor, and said resistor is no longer recognizable.

Dang. I went almost a year without smoking a single component. :)


Torben
 
The first circuit has transistors connected together without any current-limiting resistors. Smoking transistors?
The light bulb is the current limiting resistor in the circuit.
 
Both those circuits seem to have a slight design flaw.

http://www.radiolocman.com/shem/shem-cache.html?di=18800
http://www.goldsswagon.com/domedimmer/dome.jpg
They are so similar that the part numbers are the same for the parts that I am talking about.

When the door is closed, C1 eventually gets up to 12 V. When the door is opened, C1 is discharged through the switch and D1. There is no current limit in this circuit, so the current will be quite large. A 1N4148 is only rated at 450 mA peak, so the circuit should really have at least 25 Ω in directly series with C1.

It isn't good for the capacitor either. The switch will be OK with a capacitor of that size, but it is good practice to limit discharge rates.
 
So would it be correct if I were to put the switch in series right after the light bulb for the circuit in http://www.goldsswagon.com/domedimmer/dome.jpg?

cheers

According to the schematic, put the lamp in series with the 12V supply line. Then put the switch to ground from the circuit side of the lamp.

That's what I should have done, but didn't. Cost me a power resistor in my power supply that I can't even recognize anymore, it's so burned up.


Torben
 
According to the schematic, put the lamp in series with the 12V supply line. Then put the switch to ground from the circuit side of the lamp.

That's what I should have done, but didn't. Cost me a power resistor in my power supply that I can't even recognize anymore, it's so burned up.


Torben

I am so sorry, I couldn't understand what you are saying, still very fresh to this kind of stuff. Please if you could do you mind showing me a schematic? Thank you.

cheers!
 
I am so sorry, I couldn't understand what you are saying, still very fresh to this kind of stuff. Please if you could do you mind showing me a schematic? Thank you.

cheers!

The schematic is on the page you linked to.


Torben
 
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