2 inline 150 ohm resistors = __?__ on a ps2 / 3volt system

Unless I'm mistaken, 2-460 ohm resistors in parallel would be closer at 230 ohms.

@MartyE posted:

Unless I'm mistaken, 2-460 ohm resistors in parallel would be closer at 230 ohms.

You know Marty , I  couldn't find the post on " search "  that described the situation about doubling resistors but I thought there was something odd about the math that didn't apply to conventional thinking . 

What would the two resistors in parallel with the two white LEDs in series look like ?

Thanks for the quick reply........I don't like opening these locomotives more than necessary. 

Use two of the 150 ohm resistors, they'll work fine.  Truthfully, you can use one 150 ohm resistor, though that's pushing the LED right to it's rated maximum, I try not to do that.

@gunrunnerjohn posted:

Use two of the 150 ohm resistors, they'll work fine.  Truthfully, you can use one 150 ohm resistor, though that's pushing the LED right to it's rated maximum, I try not to do that.

I'm going to drop one 150 behind the other 150 on the positive line going to the two LEDs in series .

Thank you .

With two LED's in series, one 150 ohm will be sufficient.

Newly installed headlight LEDs .

A BIG  THANKS  GRJ.

It is amazing how much better the LED lighting can look over the wimpy incandescent bulbs.

@gunrunnerjohn posted:

It is amazing how much better the LED lighting can look over the wimpy incandescent bulbs.

It's hard to believe there isn't a big downside to them when you also consider the low heat , low cost and energy savings .             Thanks again John.

Well, some people complain about the color.  However, that's really not an issue if you just select the LED for the job.

From my basic electrical engineering course, putting the resistance in series just adds them together.  

R = r1 + r2

Putting them in parallel, divides them : 

R = 1/r1 + 1/r2

So in series it should be 300 ohm resistance and in parallel 75 ohm resistance.    Someone mentioned about 2 460s in parallel should be about 230.  

the 300 is probably a good solution.    the LED may be a little dimmer, but may not notice.

I don't usually try to push LED's to their max, it's pointless and just reduces their life.

There are a couple typos in prrjim's formula for resistors in parallel. The correct formula is:

R = 1 / (1/R1 + 1/R2)