Hi i am doing an electronics course at college so should know this but i cant for the life of me remeber.
Anyway, what i would like to do is put some led strips in my car just in the boot so i can see a bit clearer. This i can do. The problem is that im pretty sure that once i switch the LED's off they will still stay on dimly. The power supply is a little under 13V so a 12v supply. However when the switch is turned of there is still 11.8V or so supply. This is fine for the normal filament bulb but im thinking not so much for the LED strips.
Im sure there is a circuit that can stop the supply once it gets below a set 12V trigger.
OK, this points to the sensor and it can be normal. Now forgive me if this sounds stupid but the boot I think is what we call the trunk and the bonnet I think is the hood? Matters not but I keep trying to remember that.
Anyway, it depends on the sensor used to determine if the boot is open or closed. It may not be a simple switch. Many sensors need a load out there or leakage will show a voltage. If the sensor was chosen and designed to see an incandescent load the LEDs may not provide enough load. The trick becomes to shunt the LED circuit with a resistor.
Ron is talking about a trunk, uncle $crooge is talking about a truck...
I have never heard the term boot light but in my car the dome light (that's the french term and I figure it is also the English name for it) turns off very slowly when I close the doors like if there was a really large capacitor. Being that the dome uses an incandescent light bulb perhaps using LEDs it would takes much longer for this capacitor to discharge?
i've seen the same problem with other LED lighting devices. you're getting a few microamps leakage current through the switch. or, if it only happens with the engine running, you're picking up alternator whine capacitively coupled from other wiring. a 1uf/50V cap across the LED strip should take care of a whine induced problem, a 4.7k resistor across the LED strip should shunt any leakage current.
i've seen the same problem with other LED lighting devices. you're getting a few microamps leakage current through the switch. or, if it only happens with the engine running, you're picking up alternator whine capacitively coupled from other wiring. a 1uf/50V cap across the LED strip should take care of a whine induced problem, a 4.7k resistor across the LED strip should shunt any leakage current.