Solve Voltage Divider Problem with Vg=210V, R1=15.5kOhm, R2=66kOhm, RL=157.5kOhm

[truettct]

This is the problem.

Given that Vg is 210 V, R1 is 15.5 kOhm, R2 is 66 kOhm and RL is 157.5 kOhm, find the voltage "v0" (Hint: Use the voltage divider concept.)

My attempt at the problem was to combine R1 and R2 through series and use RL as R2 in the voltage divider formula.

The answer I came up with was 71.61V.

 

[vk6kro]

I don't get that answer.

You need to work out the parallel combination of R2 and RL. Call this R3.

Then put this in series with R1.

The output voltage can then be worked out by the voltage divider formula. (210 * R3 / (R1 + R3) )

OR, you can work out the total current (by I = Vg / Rtotal) and hence work out the voltage across each resistor using Ohms Law in the form V = I * R

 

[truettct]

Thanks.