Calculate the voltage across terminals:

A voltmeter in the 100 volt range along with a sensitivity of 40 K?/V is to measure the voltage across terminals ab.

Find:   

1.  V_o

2.  V_w

3.  K_v

Figure: Measuring Circuit Voltage

Solution:

1.  V_o = 100K?/100K? +100K? x 220V

V_o = 110 volts

2. Ro = (100)(100)/ 100+100 =50K?  R_in =SV =(40K?/V)(100V)- 4.4M?

V_w = (R_in / R_o +R_in)V_o

= (4.4 x 10⁶/50 x 10³ + 4.4 x 10⁶) (110)                               

=(0.99)(110)         

Vw = 108.9 volts

3.   K_v =V_w/V_o

=108.9/110

K_v = 0.99 or 99%