Mark42
Fleet Admiral
- Joined
- Oct 8, 2003
- Messages
- 9,334
The dark carpet in my car makes it imposable to see anything on the floor at night. So I want to add some lighting under the dash and rear seat floor area when the dash lights are on. Want to use LED lights so the additional load on the circuit is minimal.
I found these LED lights at Radio Shack, and I bought two to play with. They are 10 mm super bright LED's.
The specs on the bag are:
Absolute maximum ratings:
Forward current(if) 40mA max.
Forward Voltage(Vf) 5VDC max
Reverse voltage 6VDC
Power dissipation: 100mW
Electro-optical characteristics:
Forward voltage: 2.4V +/- 03V
Peak Emission wavelength 660nm
Luminous intensity 5000mcd (typ at 20mA)
The problem is how to make this 2.4V LED run on 12V?
In the past, I had added some LED's indicator lights, and was told to use a resistor to cut down the voltage to the LED (this from a guy working at radio shack years ago). So I connected the new LED using some of the same resistors and it works, but I'm not sure how long the LED will last with this setup.
I tested the resistors, and at 2K, they show 0.501 ohms on the multimeter.
Is this a safe way to connect the LED's? Will they last or burn out soon?
Thanks for any suggestions!
Mark
I found these LED lights at Radio Shack, and I bought two to play with. They are 10 mm super bright LED's.

The specs on the bag are:
Absolute maximum ratings:
Forward current(if) 40mA max.
Forward Voltage(Vf) 5VDC max
Reverse voltage 6VDC
Power dissipation: 100mW
Electro-optical characteristics:
Forward voltage: 2.4V +/- 03V
Peak Emission wavelength 660nm
Luminous intensity 5000mcd (typ at 20mA)
The problem is how to make this 2.4V LED run on 12V?
In the past, I had added some LED's indicator lights, and was told to use a resistor to cut down the voltage to the LED (this from a guy working at radio shack years ago). So I connected the new LED using some of the same resistors and it works, but I'm not sure how long the LED will last with this setup.
I tested the resistors, and at 2K, they show 0.501 ohms on the multimeter.
Is this a safe way to connect the LED's? Will they last or burn out soon?
Thanks for any suggestions!
Mark