#### PhillDubya

##### New Member

I have got a circuit that needs right at 24v dc. Its actually a load cell that is accurate to .1lbs. So 24V right on the dot is actually important.

So I have a transformer that is roughly 25.6vac out. I am using a an LM317 voltage regulator with: R2=1800 Ω, and R1=100 Ω.

From the formula: Vout = 1.25V(1+(r2/r1)) and thus: if R1= 100 Ω --> R2 = (24V/1.25V-1)100Ω = ~ 1800Ω.

However, from that I am getting like 17V???

Any idea why? Or what resistor combination I might use?

Edit: I understand that there is some tolerance associated with non-precision resistors, but 17V?????

Thanks

So I have a transformer that is roughly 25.6vac out. I am using a an LM317 voltage regulator with: R2=1800 Ω, and R1=100 Ω.

From the formula: Vout = 1.25V(1+(r2/r1)) and thus: if R1= 100 Ω --> R2 = (24V/1.25V-1)100Ω = ~ 1800Ω.

However, from that I am getting like 17V???

Any idea why? Or what resistor combination I might use?

Edit: I understand that there is some tolerance associated with non-precision resistors, but 17V?????

Thanks

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