Not usually one for asking questions in forums, as I'm usually able to find solutions with my own research, however, I've been looking at this over a period of days now, and the deeper I dig, the more confused I'm getting.. I'm a Computer Science student, not electronics, so please go easy on me
I need to wire up 25 white LEDs that need to be dimmed. I've opted for a PWM dimmer.
My LEDs didn't come with a datasheet or any information. I can only presume they have a voltage drop of 3 - 3.3V and a forward current of 10 - 20mA, from what I've read online.
I connected one up to a 9V PP3 battery at first, it worked... I thought they must be some sort of high voltage LEDs. I then connected one to a 3.75V Li-ion battery and it blew. I think this is because the PP3 is unable to provide as much current as the Li-ion? Someone also told me that because my PP3 was Zinc-Chloride, it had a higher internal resistance which is why it didn't kill my LED, whereas an alkaline one could potentially fry it.
I've been researching about wiring LEDs and the need for resistors but it's just getting more confusing the more I look into it. Given that my circuit is working as is and it's only for a temporary application, would it be worth it to risk leaving them out? Also the presence of the PWM should be considered. Would this lower the current flowing through the LEDs? Or should I at least use a singular resistor?
Then there's resistor wattages. How do I calculate what wattage resistor I need?
And then my main question: what's the best way to wire them in terms of preserving battery life, but without losing out on any brightness? Given that these LEDs require 3 / 3.3V and my power supply is 9V, I figured I could wire them in parallel with 2 per branch, or maybe wire a series circuit with 13 LEDs on one parallel branch and 12 on another... I came up with some, probably incorrect, diagrams depicting both of these. They're attached
Is there a better way to go about it than what I'm doing? Am I right in saying that either of these methods would get me double the battery life as opposed to just wiring the lot in parallel?
If someone could kindly explain the best way to wire this, I would be most greatful
I need to wire up 25 white LEDs that need to be dimmed. I've opted for a PWM dimmer.
My LEDs didn't come with a datasheet or any information. I can only presume they have a voltage drop of 3 - 3.3V and a forward current of 10 - 20mA, from what I've read online.
I connected one up to a 9V PP3 battery at first, it worked... I thought they must be some sort of high voltage LEDs. I then connected one to a 3.75V Li-ion battery and it blew. I think this is because the PP3 is unable to provide as much current as the Li-ion? Someone also told me that because my PP3 was Zinc-Chloride, it had a higher internal resistance which is why it didn't kill my LED, whereas an alkaline one could potentially fry it.
I've been researching about wiring LEDs and the need for resistors but it's just getting more confusing the more I look into it. Given that my circuit is working as is and it's only for a temporary application, would it be worth it to risk leaving them out? Also the presence of the PWM should be considered. Would this lower the current flowing through the LEDs? Or should I at least use a singular resistor?
Then there's resistor wattages. How do I calculate what wattage resistor I need?
And then my main question: what's the best way to wire them in terms of preserving battery life, but without losing out on any brightness? Given that these LEDs require 3 / 3.3V and my power supply is 9V, I figured I could wire them in parallel with 2 per branch, or maybe wire a series circuit with 13 LEDs on one parallel branch and 12 on another... I came up with some, probably incorrect, diagrams depicting both of these. They're attached
Is there a better way to go about it than what I'm doing? Am I right in saying that either of these methods would get me double the battery life as opposed to just wiring the lot in parallel?
If someone could kindly explain the best way to wire this, I would be most greatful