# Serial Stringing Resistors ??

Discussion in 'General Electronics Discussion' started by Raul, Oct 24, 2012.

1. ### Raul

33
0
Sep 25, 2012
When stringing different rated resistors to get more resistance (for an LED array):
Does it matter what order they are in; and if it does; does it matter what order they are in depending on whether they are the positive or negative lead from the PS?

My instinct says put the large resister closest to the power supply positive lead and the smaller one after that. But my instincts are not terribly well informed.

2. ### MrEE

84
0
Apr 13, 2012
No it doesn't matter. The same current flows through anything connected in series.

3. ### shrtrnd

3,826
527
Jan 15, 2010
Yeah, but I wonder about your statement that you want to put the large resistor closest
to the power supply.
Like MrEE said, the current will be the same through the series circuit.
Make sure, if you're using different sized resistors, that the small ones are able to
HANDLE that series current (wattage-wise).

4. ### Raul

33
0
Sep 25, 2012

The watt load of my LEDS won't overwhelm the individual resistors I have. I'm just trying to avoid paying for shipping on a dollar's worth of resistors, so I'm playing with combining them to get a resistance value at or a little above what I need.

5. ### MrEE

84
0
Apr 13, 2012
Naturally, each resistor should handle the power (given by P=RI^2) .This shows that in series connection, the largest valued resistors will dissipate the most power. When selecting resistors I'd actually use a higher rating than the actual dissipated power (double or even higher). You never know what is the ambient temperature around the resistor... Again, as far as placement, it doesn't matter where you place them.

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