hi this is my first posting here just wanted someone to help me design a circuit that glows 46 medium powered white led's with a dc 12v power supply i have designed one for ac 230 v but same circuit doesnt work for dc anyone ?
You can put 3 LEDs in series and add a resistor of ohms = 3 volts/current
or use a constant current device to reduce fading as the battery discharges.
15 strings like this will get you 45 LEDs working.
This is only one idea. There are many ways to go about this. Do you have something in mind?
You should not guess the forward voltage of your LEDs. Its range of voltage is listed on its datasheet or you can measure and record each one.
A white LED is usually 3.3V to 3.6V.
I gave you the math is post #6. Just change to using 2 LEDs in series with a resistor and you have one of 23 circuits that will be in parallel. 12-7.2 = 4.8 volts
4.8/ .025 = 192 ohms. Use 220 ohms 1/4 watt because it is a standard value that you can buy.
You can try 3 LEDs in each series string, but they will get a lot dimmer as the battery discharges compared to the 2 LED string.