M

#### Mike H

- Jan 1, 1970

- 0

to output a fixed current based on Rset regardless of input voltage.

The spec sheet says that the total current through IC is the sum of the

current going through the SET resistor and the bias current for the IC.

The formula is presented as Iset = Ir + Ibias = Vr/Rset+Ibias

The data sheet for this IC can be found here:

http://www.national.com/pf/LM/LM334.html

The question is, for a input voltage of 12 - 14 volts DC, what set

resistor should be used to reach 20mA of current?

What would the formula look like using those voltages but wanting to vary

the output current?

I guess I'm just a bit confused on how to calculate it and what all values

I need to take into account when I do so.

Any help is appreciated. Thanks.