An ideal form of a voltage source whose output Vo is controlled by an input voltage V 1 is shown in Fig. 1 1.16.
The output voltage is seen to be dependent on the input voltage (times a scale factor k) . This type of circuit can be built using an op-amp as shown in F ig. 1 1.17. Two versions of the circuit are shown, one using the inverting input, the other the nonin- verting input. For the connection of F ig. 11.17 a, the output voltage is