Consider the circuit shown in Fig. The circuit uses an ideal operational amplifier. Assuming that the impedances at noodes A and B do not load the preceeding bridge circuit, calculate the output voltage V_o.

when $${R_a}\, = \,{R_b}\, = \,{R_c}\,{R_d}\,$$ ohms.
when $${R_a}\, = \,{R_b}\, = {R_c}\, = 100$$ ohms and $${R_{d\,}}\, = \,120$$ ohms.

The circuit of fig. uses an ideal OP_Amp for small positive values of V_in, the circuit works as

Assume that the operational amplifier in figure is deal the current I through the IK ohm resistor is

The JFET in the circuit shown in fig. has an I_DSS = 10mA and V_p = -5V. The value of the resistance R_s for a drain current I_DS = 6.4mA is (select the Nearest value).