I have a 16x diode need advise

[Leodahsan]

four resistors of 1ohm each in series, will result in 4ohm, giving you 310mA in a lm317 configuration.
if you want more, you can remove a resistor and crank the diode 410mA, but I do not recommend unless you know what you are doing.

 

[drewk302]

ok I see, I was thinking or parallel where if you add 2 or more resistors it cuts the resistance of the resistor in half. I see u said wire them in series, thats perfect then. Thanks for your help!

 

[Leodahsan]

no problem. as you said you can always get 3x 10r resistors and wire them in parallel for 3.5r

 

[anselm]

parallel where if you add 2 or more resistors it cuts the resistance of the resistor in half.

derp.

N resitors in series:
Rt=R1+R2+R3+...+Rn
N resitors in parallel:
1/Rt=1/R1+1/R2+1/R3t+....+1/Rn

Using these two equations, you can create ANY equivalent resistance, if you need
one that is not sold by itself.

I got all of my resitors, capacitors, diodes and what-have-you by desoldering them from
electronic junk like wireless phones, transformers, PC power supplies, DVD players....

(r): I don't really know if you people use that designation,

No we don't, not that I know of. Not in english, portugal and germany at least, that is.
What unit does "r" stand for anyway?

 

[drewk302]

You are a HUGE help. But I am deffinately a slow learner, can you break down the N resistors in parallel equation, I am confused. Sorry, Thanks.

 

[Leodahsan]

@anselm
r = ohm.. 100r 10r 1r = 100ohm 10ohm 1ohm...

 

[drewk302]

haha 2r2 umm nope. but this: N resitors in parallel:
1/Rt=1/R1+1/R2+1/R3t+....+1/Rn....confuses me also???

 

[Leodahsan]

^I wasn't fast enough.

click me

 

[LordKaramazov]

It stands for Ohms...and yes, in Portugal that designation is also used...

Here in germany im not sure, but if u go (just as an example) to Dimofel (in Lisbon) they use the r designation...and lots of other stores...The electronic store where i buy stuff in Coimbra also uses r... its common i think.


And to OP, id also recommend a capacitor in the circuit to cut high frequencies, so u wont have a voltage spike in ur diode and kill it.

Or do u expert people in DIY drivers think its ok just like that?


(only used flexdrives so far...tiny spaces require tiny driver )

 

[LordKaramazov]

Damnit Leodashan! U beat me to it!

Portuguese speakers discussion now xD


What he means with parallel thingies is:
Rt is total resistance (so Ohm). So if u get all ur resistors in parallel, it means that ur total resistance to the minus 1 power (aka 1/Rt or Rt^-1) equals the sum of all the inverse of the resistors, so:

1/Rt= 1/R1 + 1/R2 + 1/R3 + ... and so on

 

[Leodahsan]

^lol'ed
Great thing to hear too, I think only here in BR the designation was used.

 

[drewk302]

Thats awesome! Thank you.

 

[anselm]

...can you break down the N resistors in parallel equation,

I wouldn't know how to break it down any further.:crackup:

Maybe a couple of examples will make the penny drop:

1Ohm + 1Ohm:
1/Rt = 1/1 + 1/1 <=> 1/Rt = 2 <=> Rt = 1/2

1ohm + 5 ohm + 10ohm
1/Rt = 1/1 + 1/5 + 1/10 <=> 1/Rt = 13/10 <=> Rt = 10/13

 

[jib77]

R = resistor and its used as the decimal designator on the value printed on some resistors. K is used as the thousand separator.
1R00 = 1 ohm
10R0 = 10 ohm
R033 = 0.033
10K0 = 10,000 ohm

You can also have it where the last number is the number of 0's left out:
101 = 100 ohm
102 = 1000 ohm
103 = 10000 ohm

Edit: dang y'all are fast

 

[Leodahsan]

THANKS a lot for explaining, jib.
did you read what jib posted, anselm? 2r2 = 2.2ohm
PS:You must spread some Reputation around before giving it to jib77 again.

 

[drewk302]

You guys are great! I gotta say math is my weakness. i did get a link to a parallel resistance calc. that helped, I gotta work on figureing out those equations ( wow I am slow ). I really waned to do this driver like this, so I can learn. I am building the 1.6w blue like i seen on this site after this one, but I will be buying the driver premade and so on. On this one looks like I will be using a 10ohm - 10ohm -15ohm in parallel to get me a resistance of 4.2 ohm, with the lm3117 and get 300ma. Using 7-8volt lith-ion. It seems right to me, any other suggestions?