High Powered White LED torch.

[Canyouknott]

Hey guys, I have been looking all over the net for a description on how a High powered led circuit works and what components is involved... I have yet to find a diagram which explains to me what is actually happening....

For this project I just want to make a torch which involves a strong White LED running off 9 < Volts.

Does anyone time to make a quick diagram of a circuit which could be used for this activity and also explain how it works?????

Thanks so much

 

[Joe G]

have you ever checked out https://www.candlepowerforums.com

 

[audioguru]

I have a very cheap Chinese flashlight (Torch for Brits) that has 24 matched white LEDs in parallel and the internal resistance of the three series very cheap "Super heavy Duty" AAA cells limits the current.
An LED has a maximum allowed current and will soon burn out if your circuit exceeds that current. An ordinary 5mm diameter LED has a maximum current rating of 30mA or 40mA and its brightness is rated at 20mA.

For testing the forward voltage of an LED I use a 9V alkaline battery and connect a 330 ohm resistor in series with the LED.
A red LED is about 2V so the resistor has 9v - 2V= 7V across it and the current is 7V/330 ohms= 21mA. A white LED is about 3.2V so with the 330 ohm resistor the current is 17.6mA.

Using such a high supply voltage as 9V for a 2V or 3V LED wastes a lot of battery power. Then an efficient voltage converter circuit is used to replace my 330 ohms resistor.

 

[Canyouknott]

Oh I see, thanks for the explaination

 

[KeepItSimpleStupid]

High power light: https://www.streamlight.com/en-us/product/product.html?pid=261

 

[ronsimpson]

Here is a circuit. It is designed to take power from a battery at 6 volts and drive an LED at about 3 volts. If a resistor was used to limit the current only half of the power would get to the LED and the other half would be lost in the resistor. This IC takes the battery voltage of 6V and sends it to the point "SW" half of the time and sends 0V for the other half of the time. (switches very fast) The "L" and "Co" makes a filter that averages this voltage to 3 volts. The power loss is very small. The IC watches the LED current (via Rs) and adjusts the duty cycle (50%/50%) to get the right current in the LED. If the battery voltage drops to 3.1 volts the IC will be on 100% and off 0% giving the LED 3.0 volts.