Practical Electronics/Voltage Divider

Intro
A network of two resistors connected as shown

Analysis

 * Vo = I R2
 * $$I = \frac{V_i}{R_1+R_2}$$
 * $$V_o = I R_2 = \frac{R_2}{R_1+R_2} V_i$$

Formula

 * $$V_o = \frac{R_2}{R_1+R_2} V_i$$

Choosing Value for R

 * R2
 * R2 = 0, Vo = 0
 * R2 >> R1, Vo = Vi


 * R1
 * R1 = 0, Vo = Vi
 * R1 >> R2, Vo = 0


 * R1 = R2
 * Vo = ½ Vi


 * When R1 = R2, the output voltage is exactly halved of the input voltage

Summary
There is no gain for this network, since Vo never greater than Vi.

This network can be used as Voltage Attenuator, Voltage Follower, Voltage Halved, or Voltage Ground


 * When the value of R2 > R1, this network acts as Voltage Attenuator


 * When the value of R2 = 0 or R1 >> R2, this network acts as Voltage Ground


 * When the value of R1 = 0 or R1 << R2, this network acts as Voltage Follower


 * When the value of R2 = R1 = R then this network acts as Voltage Halved