A design problem: As we said earlier, the backbone of any design is ‘thorough analysis' of the problem or circuit at hand. We have analyzed above the voltage divider circuit. Utilizing the above analysis, determine R1 and R2 of a voltage divider circuit to satisfy the following specification:
specification: An automobile chassis display light having a resistance of 400ohm requires for its proper operation 9 V with a tolerance of ±5%. Design a voltage divider circuit that gets its supply voltage from the automobile battery, and feeds its output to the chassis display light. We are also told that the output voltage of the voltage divider should be at 9 V with a tolerance of ±5% whether the chassis display light is on or off.
Hint: Note that vg is the battery voltage, and hence vg = 12 V. We need to determine R1 and R2. Take the voltage vout of the voltage divider circuit under no load (when the chassis display light is switched o?) as 9 + (0.05)9 = 9.45 Volts. This gives one equation between R1 and R2. Next, take the voltage vout of the voltage divider circuit under load (when the chassis display light is switched on) as 9 ?(0.05)9 = 8.55 Volts. This gives another equation between R1 and R2. Solve the resulting two equations for R1 and R2.