Question

I am having some trouble finding the values of the Rf (potentiometer) and R resistors for the following circuit (Right Leg Driver (RLD)). The circuit should have an adjustable gain from -1 to -10, and a 100kOhm output protection resistor (Ro). When I wrote the expression of the gain, I could not find the values of Rf and R that satisfies the abovementioned condition.

UX1 RO O UX2 <RLD GND output Add a right leg driver stage with adjustable gain from - 1 to -10. Include a 100k protection resistor.

Answer 1

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Given Circuit to Vout Vxz . R Vout due to Vx, :o - Vout = ef Vout due to Vxz: - Vaut = -RF Vez Total Vout Vout = - Rr VX + (1 - 2 Vesz)

Vout - - R (Vx, + Vx2) 2R = Vout Voltage gain, Av ē. 1 x + Vxz - Rf AV = Vout S Vx, +Vxz ZR gain iven is fom - to -10 Let R=1KR fof AV = -1 for - =-Rf 2x1K R [R = 262 | Av = -10 -10 = - RF ZXIKR R = 2002

Resistos Value R=1kr potentiometer range RF = 2 K2 - 2002 range of potentiometee is from 2K2 to 20kr.