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You've missed the point about a single transistor!.
Connect the LED back in the collector where it was (with it's series resistor), connect a resistor from base to HT, and connect the switch from base to ground!.
Just as houseofwax implied, why don't you just use a normally closed switch like every other glovebox on the face of the planet? When the glovebox is closed and the switch is pushed, then the light will be off. Open it and the switch contacts will close......
With the 360 ohm resistor in series with the LED and a 9V supply, the transistor's collector and the LED have a current of (9V-1.8V)/360= 20mA if the LED is a 1.8V red one. The transistor has current gain so its base current should be a max of 20mA/10= 2mA. Then the base resistor should be about (9V-0.7V/2mA= 4.2k ohms.
Why does your circuit have a base resistor of only 100 ohms? Then the base current is more than 42 times too high. It will get very hot because it wastes a lot of power.
Ok thanks everyone, sorry for being SO stupid.
I dont have a push to break switch.
My circuit only had a 10ohm resistor because i have very little idea what im doing.
My knowledge is growing day by day, but im still in the early stages of understanding exactly whats going on.
When the switch is pushed ( ie when glove box is closed ) you will be losing power through the resistor. The battery won't last very long.
Seriously, you're much better off rounding up a push to break switch. That way you only need the battery, switch, led and current limiting resistor. If you get a lever operated microswitch it should make mounting it easier too.
Alternatively you could use a tilt switch attached to the inside of the glove box door.
What make / model of car is it ? I don't think I've ever had one that didn't have a light in it.
Vauxhall Corsa, no idea what model. Upon closer inspection it does have a light in it, but it just doesnt work, it must have broken long before i got it.
I cant seem to open the door up, or remove the covering of the broken light. Any ideas?
I appreciate what your saying about the resistor draining power, as this is what i anticipated would happen (and is the reason
why I started this thread).
As a guess, I'd say that the light surround usually pops out if you insert a thin bladed screwdriver just behind the clear / white bezel and prise it slightly. Try it a bit one end, then the other.
Admittedly car manufactureres are quite good at disguising clips and screws etc, but it is possible somehow. Keep trying.
ok thanks. If i can get at the light, and provided the switch is not broken, then surely i could just multimeter the light terminals, and use a resistor- led combo to fix?
Your latest circuit will work, though as I've stated before 'waste power'.
Though since you already have a switch in the box, go with that one. It's a 'push to break' for a reason.
Your latest circuit is fine to turn on and off the LED.
An ordinary LED shines in a narrow beam. The light bulb is brigher and shines all around. A light bulb is what you should use for a glove box in a car.
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