Before the advent of ohmmeters even the analog ones unknown

Last updated: 6/19/2023

Before the advent of ohmmeters even the analog ones unknown resistances Runk were measured using a Wheatstone bridge The unknown resistance is placed into the circuit at right as shown The values of R and R are extremely well known The resistance of Rvar is adjusted until the meter reads no current in the cross branch The value of Rvar is then read from a dial www Show that Runk can be found from Rukn R Ry R Runk ww R Rvar