Question

b. You now add an Op Amp (powered by ±5V) to the voltage divider. For this circuit, provide a governing transfer function. If Vin=5V, calculate Vout at the following two conditions: 1) R=100Ω and RS=100Ω, and 2) R=100Ω and RS=105Ω. Calculate sensitivity in units of Volt/Ohm. Show all work. (5 points)

Answer 1

1) Vout = -25 V

2) Vout = -25.61 V

The sensitivity is 0.122 V/Ω

Step-by-step explanation:

The equation for Vout is:

`V_(out) =-(R_(f) )/(R_(i) ) ((V_(in)R_(s) )/(R_(str) ) )`

1) Given:

Rf = 10 K

Ri = 1 K

Rs = 100 Ω

Rstr = 200 Ω

Vin = 5 V

`V_(out) =-(10)/(1) ((5*100)/(200) )=-25V`

2) Now, Rs = 105 Ω

`V_(out) =-(10)/(1) ((5*105)/(205) )=-25.61V`

The sensitivity is equal to:

`S=(V_(out2)-V_(out1))/(R_(s2)-R_(s1) ) =(25.61-25)/(105-100) =0.122V/ohm`