Author Topic: Is this circuit good?  (Read 4698 times)

Offline i7vSa7vi7y

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Is this circuit good?
« on: January 14, 2016, 03:42:18 PM »


« Last Edit: January 14, 2016, 06:16:52 PM by i7vSa7vi7y »

Offline Modded Matt

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Re: Is this circuit good?
« Reply #1 on: January 15, 2016, 05:45:12 AM »
Depends on if your LED's can run off of 0.85V each which I highly doubt.  When wiring in series the voltage of the source is dispersed equally throughout all of the LEDs. In order to find out how much power will be going to each LED you divide the voltage of the source by the number of LEDs.

You need to wire them in parallel not series or use a larger power source which you dont have. 


Offline i7vSa7vi7y

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Re: Is this circuit good?
« Reply #2 on: January 15, 2016, 07:14:41 PM »
How much voltage will they be getting parallel?

Offline RDC

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Re: Is this circuit good?
« Reply #3 on: January 15, 2016, 09:50:48 PM »
Your wiring to the switch is incorrect also. Wiring it how you have it drawn there connected to the outside leads of the switch, nothing will ever happen in either position. You need to use the center lead for the 3.2v, and then either one of the outside leads to go to the LEDs.

You are also going to want a Resistor on each LED in your parallel setup. Google up LED Calculator, there are several of them out there that can do all of the math for you. You only need to know the LED forward voltage and current specs, which the place you bought them from should have, then the source voltage, which you know is 3.2v for that controller, and is what every LED will get wired in parallel.
« Last Edit: January 15, 2016, 09:52:11 PM by RDC »
Screwing up is one of the best learning tools, so long as the only thing you're not learning is how to screw up.

Offline i7vSa7vi7y

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Re: Is this circuit good?
« Reply #4 on: January 17, 2016, 09:01:48 AM »
Thank you very much. Haven't done any LED mods for about 3 years since PS3. Would I need a resistor if my LEDs are 3.0 and max 3.5? I've held a LED on the points on the analog for a while and it didn't get hot at all.
These are my LEDs
http://www.unique-leds.com/index.php?target=products&product_id=1646



Also would I be able to make that single switch illuminate LEDs and then in the opposite position illuminate them only with the rumble packs or would I need another switch?
« Last Edit: January 17, 2016, 09:06:06 AM by i7vSa7vi7y »

Offline RDC

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Re: Is this circuit good?
« Reply #5 on: January 17, 2016, 12:29:05 PM »
You should always use a Resistor on each LED in a parallel circuit. Given the rating of them and the source voltage, a 10Ohm on each one should be used.


You can try this for your Rumble LED switch...

Connect all of the LEDs Anodes (positive side) to the 3.2v source, thru the appropriate Resistors first.

Connect all of the LEDs Cathodes (negative side) to the center lead of your switch.

Connect one of the outside leads of the switch to a Ground spot. With the switch in this position, the LEDs will light up when the controller is on.

Connect the other outside lead of the switch to one, and only one, of the Rumble Motor's black leads. With the switch in this position, the LEDs will only light when the controller is on and that Rumble motor is working.
Screwing up is one of the best learning tools, so long as the only thing you're not learning is how to screw up.

Offline i7vSa7vi7y

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Re: Is this circuit good?
« Reply #6 on: January 20, 2016, 07:07:18 AM »
Thanks you're a big help and fast replys! I good vote your every post. I used a 10-kohm 1/8-Watt Resistor and the LED wasn't bright at all. If the LED max is 3.5 and the = points are only 3.2 why do I need a resistor? Will the LED not last as long? Ifso how long will it last?

Offline Modded Matt

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Re: Is this circuit good?
« Reply #7 on: January 20, 2016, 09:56:38 AM »
You should always use a resistor to protect the circuit.
You need to use the normal operating forward voltage (not the max)
Your resistor should be 5 OHM to supply 3.1V to your LED.


Where did you get 10-KOHM? Use this:

http://led.linear1.org/led.wiz

Offline RDC

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Re: Is this circuit good?
« Reply #8 on: January 20, 2016, 10:02:32 AM »
10k is 10,000 Ohms, not 10Ohm, which is 10 Ohms and what I suggested. ;)

The MAX rating of the LED is 3.5v, that's not the nominal rating and the MIN rating was 3v, where you will be using a 3.2v source. You can Google up LED circuits and basic electronics all day long if you need the full details of why you should use a Resistor, or just run them how you like if you believe that just because it works for now is a good enough reason, but I'd use a 10Ohm on each one as it's just safer, and you're not going to really even notice it's in there compared to running it straight, versus that incorrect 10k you have in there now.

Screwing up is one of the best learning tools, so long as the only thing you're not learning is how to screw up.

Offline i7vSa7vi7y

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Re: Is this circuit good?
« Reply #9 on: January 20, 2016, 12:21:58 PM »
Dammit!!!! Yeah I read because LEDs use maxvoltage and its unregular without a resistor. I went to radioshack and they only had one 10 and thats what the guy gave me. I didn't pay attention since they looked really small lol. Damn. Does radioshack have them or should I just get them from ebay?

The calculator says I need a 5.6 ohm 1/4w.

3.2v
3.1
20mA
1 since I'm not running them parallel

The wizard says: In solution 0:
each 5.6 ohm resistor dissipates 2.24 mW
the wizard thinks 1/4W resistors are fine for your application Help
together, all resistors dissipate 2.24 mW
together, the diodes dissipate 62 mW
total power dissipated by the array is 64.24 mW
the array draws current of 20 mA from the source.

A different calculator says I need 5.6 1/8w

So is this good http://www.ebay.com/itm/50x-5-6-Ohm-1-8W-Carbon-Film-Resistor-5-5-6R-5R6-DE2769-/310725478092?hash=item4858ae86cc:g:AZcAAOSwfcVUHOFT
« Last Edit: January 20, 2016, 12:31:35 PM by i7vSa7vi7y »

Offline GhoSt

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Re: Is this circuit good?
« Reply #10 on: January 20, 2016, 09:21:11 PM »
So is this good http://www.ebay.com/itm/50x-5-6-Ohm-1-8W-Carbon-Film-Resistor-5-5-6R-5R6-DE2769-/310725478092?hash=item4858ae86cc:g:AZcAAOSwfcVUHOFT
That will be fine, as long as you drop like less 0.8V over it, which you almost certainly will with a 3.2V diode in series with it (and a ~3.2V supply).

Any of your supply voltage not dropped over your LED is dropped over this resistor, so the resistor and voltage deficit determine current flowing in the hole shebang. This is why you should always have a series resistor, otherwise you get a fat current flowing through your LED and toast that bad boy (don't worry we've all done it at some point in our lives).

Good luck. It may be worth just buying a whole bunch of different valued axial resistors, like a bulk 1/4W  kit or something (10R - 100K?), probably the most useful thing to have around if you are planning on getting into electronics. 
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Offline RDC

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Re: Is this circuit good?
« Reply #11 on: January 21, 2016, 03:12:30 AM »
Those 1/8W are fine, as they are 125mW (1000mW = 1W) and you're dissipating nowhere near that value.
Screwing up is one of the best learning tools, so long as the only thing you're not learning is how to screw up.

Offline i7vSa7vi7y

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Re: Is this circuit good?
« Reply #12 on: January 21, 2016, 02:26:00 PM »
Thanks for all the help. I ended up just going to radioshack and getting the 10 ohm 1/8w and they work perfect. I'll be sure to post the mod once I'm done.

 

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