A little confused with Regulators and resistors

[Madshock]

Hi All,

Appreciate some help here. As im not really an electronic savvy person, I got confused by 2 items when i was sourcing for parts.

I have now, the basic materials for a 3.7V box mod. However, being adventurous, i decided to get the materials for both 3.7V AND 5V. and then it struck me.. Yes i know there is a need for a 5v regulator if i want to attain that sweet spot BUT, with so much regulators and tech jargons, i have no idea which one i need to get... Additionally, i know there is a need for a resistor(470ohms) for my 3mm LED, however, THEY also have too many specs to look at...

Thanks in advance~

 

[Shortstuff116]

As far as the LED and resistor are concerned, you can go to this page and by putting the correct numbers in the boxes it will calculate which size resistor you should use. So many times I read about using 470 ohm resistors which is not near what you should use for the basic 3mm and 5mm LED's we normally use in our mods.

For example: If you are using a simple 3mm Red or Green LED, then using 3.7 volts as the "Supply Voltage" and 2 volts as the "Voltage Drop" and 20mah as the "Desired LED Current" then you should come up with needing only a 100 ohm resistor.

 

[bassthumper]

I couldn't have found this post at a better time
I was in this EXACT situation-- had everything I needed but the resistor bc I was like wtf...

 

[WillyB]

As far as the LED and resistor are concerned, you can go to this page and by putting the correct numbers in the boxes it will calculate which size resistor you should use. So many times I read about using 470 ohm resistors which is not near what you should use for the basic 3mm and 5mm LED's we normally use in our mods.

For example: If you are using a simple 3mm Red or Green LED, then using 3.7 volts as the "Supply Voltage" and 2 volts as the "Voltage Drop" and 20mah as the "Desired LED Current" then you should come up with needing only a 100 ohm resistor.

While I tend to agree many get their LEDs from the supplier who does not provide any specs. The calculator you linked to is fine if in fact you desire full brightness, most might prefer it a little dimmer. Something higher than 100Ω may be more desirable.

 

[Madshock]

Thanks for the replies!!!

in the end i went for a 68ohm resistor to aim for maximum brightness at 20amp.

If i find it too bight, can i just double up the resistor by putting them in series?

 

[Madshock]

As for the 5v Regulators..

Should i get 5v 3amp? 5v 5amp?

Since My USB PT is only getting 3.4V from my usb port.
I would say 5v 1amp is the same results as my USB PT? (i hope im not associating the wrong stuff here)

 

[derek88]

As for the 5v Regulators..

Should i get 5v 3amp? 5v 5amp?

Since My USB PT is only getting 3.4V from my usb port.
I would say 5v 1amp is the same results as my USB PT? (i hope im not associating the wrong stuff here)

3 Amp is more then enough for our application.

 

[Madshock]

Thanks Derek88!

I guess that sums up all i need to get started on my Modding journey!

Bhahaha, 5v DIY PV here i come!

 

[48lowes]

I purchased some led's on ebay. It stated that they were bright. I wired it with a 100Ω resister and it was so bright when I put my thumb over it you could see the light through my thumb. I now either use a higher resistance or just drill a small hole ⅛″ and put the led behind it.

 

[Madshock]

if thats the case can i just double up my resistor (Line it up in series) to reduce the brightness?

and another thing, for my regulators, i am only able to get my hands on 5v 5amp. it doesnt really matter for the Max Amp rite? since end of the day im still dealing with the resistance of atties and voltage output. I hope i got the facts rite.

 

[roadrash]

if thats the case can i just double up my resistor (Line it up in series) to reduce the brightness?

My 2 Ps, yes.

 

[Shortstuff116]

Madshock follow the below link and you'll find an explanation about resistance and two really handy calculators to tell you how to use resistors in parallel and in series.

Go Here

 

[AttyPops]

WARNING: Just a note for the bright LED post above....

Some "super bright" LEDs can actually hurt your eyes. Also, some LEDs are made as flashlight bulb replacements, used in special circuits (even telecom- usually IR tho) etc.... Just stick to standard LEDs unless you check out the lumens. You probably don't want super brights unless you have a specific need for them. Super-brights are more expensive anyway. Sometimes you can get a "grap bag" of misc led's real cheap.

Just FYI.