Can you power an LED with 12v?
Connect the positive terminal of the 12 volt power supply to one side of the resistor. Connect the other side of the resistor to the anode of the LED. Check the LED data sheet to identify the anode and cathode. The cathode is commonly the shorter lead and located nearest any flat side of the LED.
Can a 5V LED run on a 12v?
1 Answer. Putting two in series is not going to work, since you’d then have to interface the serial data line. You could however use a small DC-DC (such as the many LM2596 based) to convert 12V down to 5V. It would also reduce the current requirements in the wiring.
What should the current be for 3V LEDs?
We have a 8.4V drop across each resistor, and 20mA current so we get 8.4*0.02 = 0.17W for each resistor. Since your resistors are 1/2 Watt, 0.17W is well within the limits of the resistor. On a side note, 420 Ohm resistors are less common that 470 Ohm resistors, so just use 470 Ohm resistors.
Do you need a series resistor for 3V LEDs?
Firstly, either apply the three LEDs in series, with one resistor in series, or if you must have them in parallel, each will need a series resistor. The above indicative values of resistors are assuming 20 mA per LED as optimal. Do your own calculations for your specific LEDs.
How many LEDs are in a 12V circuit?
Both resistors are 1/2 Watt. LEDs are 3.6v max. By decoding your question, this is what I arrive at: You are using the two resistors as a voltage divider, with the LEDs wired in parallel connected to the junction of these two resistors.
Can a voltage divider be used to divide LEDs?
This is not a valid approach, the voltage divider will not provide the 1:4 (approximately) voltage division your calculations indicate. Firstly, either apply the three LEDs in series, with one resistor in series, or if you must have them in parallel, each will need a series resistor.