Question

Determine the resistance values for a voltage divider that must meet the following specifications:_______.

Answer 1

Answer:

i) when circuit is unloaded : R1 + R2 = 2kΩ.

ii) when 5V output voltage is applied :  R1 = 1 kΩ , R2 =  1 kΩ

iii) when 2.5 v output voltage is applied : R1 = 1500 Ω,  R2 = 500 Ω

iv) when: R1 = 1 kΩ , R2 =  1 kΩ  is connected in parallel output voltage < 5 V

When : R1 = 1500 Ω, R2 = 500 Ω is connected in parallel output voltage > 2.5V

Explanation:

Current drawn from source under loaded condition ≤ 5 mA

source voltage = 10 v ,  required output = 5 v , 2.5 v

attached below is the sketch of the circuit

Resistance values

i) when the circuit is unloaded

Req = R1 + R2 = 2 kΩ  ( Req = Vs / I  = 10 / 5*10^-3 = 2 kΩ )

ii) when  output voltage = 5 v

we will apply voltage divider rule

R1 = 1 kΩ ,

R2 =  1 kΩ

iii) When the output voltage = 2.5 v

applying voltage divider rule

R1 = 1500 Ω

R2 = 500 Ω

iv) when the load is connected to each tap one at a time

i.e. when the resistance are in parallel

when: R1 = 1 kΩ , R2 =  1 kΩ  is connected in parallel output voltage < 5 V

When : R1 = 1500 Ω, R2 = 500 Ω is connected in parallel output voltage > 2.5V

attached below is the detailed solution to the given problem