5 % resisters for SOZ?

[Selfmade]

Is it possible to use 5% restisters (R1-R8) for the SOZ or is absolutly necessary to use the qualities (1%, 0,1 %) mentioned in the NP article?

regards

Günter

 

[Henrik]

To obtain a low diffrential dc off set you need resonable matced resistors. You can parallel the higher values with some resistor to match the lower value. The formula for this is R=1/((1/R1)+(1/R2)).

 

[stefanobilliani]

To obtain a low diffrential dc off set you need resonable matced resistors. You can parallel the higher values with some resistor to match the lower value. The formula for this is R=1/((1/R1)+(1/R2)).

Or ... R = ( R1* R2 ) / (R1+ R2)
🙄

 

[Selfmade]

thank´s for you answer.

Are 25 Watt enough for the resisters R1-R8 to build a 10 Watt SOZ? For this values I can find 1 % resistors.

regards

Günter

 

[Henrik]

10 watt output requires psu at +-25 Volt, which gives a total current draw at about 4.5 A. This means a little less than 50 W dissipation in all 8 Ohm resistors. I would go for 75W each just in case. You can parallel 3*25W to obtain one resistor at 75W.