Poteniometer question??

M

mgeno216

New Member

• Apr 25, 2010

• #1

So i need these values of pots:
25 Ω x2
30 Ω x1
50 Ω x1
I need them to have a knob with a similar shape (i am going to put a colored cap on them). The only problem is that they are obscure values. Is there something that can be done to change the values like you can with regular resistors. for example 2 500Ω reisitors in paralell is 250Ω of reisitance.

Thanks,
Mike

 

MikeMl

Well-Known Member

Most Helpful Member

• Apr 25, 2010

• #2

What is the application? How much current are you drawing off the wiper?

 

M

mgeno216

New Member

• Apr 25, 2010

• #3

for controlling the brightness of leds. 80-100ma per pot

 

C

colin55

Well-Known Member

• Apr 25, 2010

• #4

You can add a transistor to take the current.

 

Sceadwian

Banned

• Apr 25, 2010

• #5

Or a simple 555 PWM driver so that you're not wasting all that power as heat.

 

MikeMl

Well-Known Member

Most Helpful Member

• Apr 25, 2010

• #6

If you are using the pot as a rheostat (connections to one end and wiper only) for LED brightness control, then the actual end-to-end resistance of the Pot doesn't matter much. Just get the next higher resistance than you think you need. Don't forget to put a fixed resistor in series with the pot to set the maximum current when the pot is shorted out...