This article solves the problem of determining the smallest and largest resistances measurable on a bridge with a given accuracy, given the specified current sensitivity limit of the galvanometer and its internal resistance, under the following conditions: with a given electromotive force of the battery and its internal resistance; with a given current flowing through the unknown resistance; with a given power dissipated across the unknown resistance; with a given power consumed by the entire bridge. The first case is the most complex. It is considered only for the Wheatstone bridge. Furthermore, the article shows that when measuring small resistances, both bridges — Thomson and Wheatstone — can be used with equal success.