Question

A circuit is supplied with 30 VDC and contains three resistors connected in series. The value or R1 is 80 , the value of R2 is 1,000 , and the value of R3 is 4,200 . What is the voltage drop across R2?

Answer 1

One approach to solving this is to first calculate the current the will flow through all three resistors:

The total resistance is R1+R2+R3 = 5280

I = V/R = 30/5280 ≈ 5,682 mA

Then the drop across R2 = I*R2 = 5,7mA * 1000 ≈ 5.682 V.

So this is based on the fact that V=I*R and there is one current running in the entire chain, ie., it is the same through each resistor.