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General Category => Your projects => Topic started by: mushpop on December 30, 2011, 03:30:26 AM

Title: Indoor Car LEDs dimmer
Post by: mushpop on December 30, 2011, 03:30:26 AM
Hi,

I would like to share this simple schematic comprise of Giorgos Lazaridis's LED Off Delay circuit and REUK's  LM2940VT-12 circuit diagrams. I'm totally new with electronics. Would be nice if someone could rectify any mistake I made with the schematic.

(http://img543.imageshack.us/img543/6030/leddimmer.png)
In the diagram I use LM2937 circuit diagram.
Title: Re: Indoor Car LEDs dimmer
Post by: kam on December 30, 2011, 09:41:45 AM
hello mushpop
i suppose you've used this circuit (LED Off Delay with dimming effect (http://pcbheaven.com/circuitpages/LED_Off_Delay/)). C1 must be some 0.1uF capacitor, and the regulator is LM2937-5.0 right?

If you do not forget the limiting resistors on the LEDs (after J2), then the circuit looks ok.
Title: Re: Indoor Car LEDs dimmer
Post by: mushpop on December 30, 2011, 10:53:38 AM
Thank you, kam.

Actually i just combined circuit from this website (http://www.reuk.co.uk/LM2940-12V-1A-Low-Dropout-Regulator.htm) with LED Off Delay Effect. From the website, it suggest to use at least 22uF for C1. I'm not sure yet what is the voltage required for aftermarket car dome light LEDs (12V or 5V). These 2 dome lights will be fixed in parallel underneath the dashboard to illuminate the feets area for both driver and passenger. Do I still need to add resistors connecting from J2 to the LED dome light?
Title: Re: Indoor Car LEDs dimmer
Post by: kam on December 30, 2011, 12:39:51 PM
usually, aftermarket car LEDs require 12V to operate and no resistor is needed. So you do not need to use the regulator.