please take a look at the following circuit and tell me what can I do wrong. My problem is that the dome lamp stays always on even the current at pinout 6 of the IC decreseas. Could the transistor be broken? Do I MUST use variable resistors? Normal 220K and 10K resistors won't work? And one more. Where should i bond the base of the transistor?? Before the 10K or after?
Hi, VR1 helps you to set time of dimming, and VR2 sets brightness. You could replace VR1 with a resistor, but to replace VR2 you need two resistors in series with base connected between them. The transistor stays always on because the voltage on the output of U1 does not go low enough (less than 0.6V measured from ground) Hope that helps.
Dome light dimmer for Cars
Posted - Mar 04 2003 : 6:04:49 PM
