Resistor value

[Clarence3815]

I need to reduce a 5v feed to 2v. Can anyone advise what value resistor I need please?

Bernard

 

[PaxtonP4]

I need to reduce a 5v feed to 2v. Can anyone advise what value resistor I need please?

Bernard

What's the current? V = I x R

 

[Clarence3815]

LED 20ma

 

[smgee]

It depends on the forward voltage drop of the LED, but for 2V, 150 ohms.

R=V/I
so Voltage across resistor / current in A = 150

There are lots of online calculators if you want to adjust the values. This one looks easy to understand:
LED Resistor Value Calculator | RS

 

[Clarence3815]

Thank you very much.

I`ll add that to my favourites.

Bernard

 

[michael080]

Correct formula above, but 20mA current through the LED result in a very bright illumination. In many cases, 5mA might be enough, so 560 Ohm might be an alternative

Michael