How to drop from 12vdc to 2vdc? Answered


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How to drop from 12vdc to 2vdc?

 I have some 12volt rocker switches that I have bought for my boat livewell pumps. They have a led light that is supposed to go on when I turn the switch but it doesn't. It says I needs DC 2V 10mA-20mA for LED Light to work. The switch works ok with the pumps, I just would like to have the led on when it operates. How do I drop from 12vdc to 2vdc so I can bring power to the leds?

Thanks to all.



Give it 1KOhm.



Hi, Thanks for the replies guys. I have found some precision numbered resistors in my stuff and would have a question about them. These are the closest to 1 kohm I could find in terms of value. There are some numbers on it as well as letters, Here it is: Dale 9540J RN55C 1871F. Now, according to my software, they would be either 954 ohms (0,954kohm +/- 5%) with the first number or 1870 ohms (1,87 kohms +/- 1%) with the second one. Which one is good? Thanks again

Of course, if you've already applied 12V to a 2V LED, it may no longer be an LED...

I suggest you add a resistor, something like 720 Ohms in series.

the LED needs 2 volts. The LED will draw 10mA So 12 volts from the battery - 2 volts for the LED = 10 volts dropped by a resistor. using Ohms law - R=V/I R= 10 volts / .010 amps = 1000 ohms or 1K ohm. 20 Ma would call for 500 ohms and a nice mid point 750 Ohms. or the nearest value.