Leeds & Northrup Enclosed-switch resistance box model 4775

Enclosed switch resistance box with 4 dials going from 0 to 9 enclosed in a bakelite case.

Figure 1: Enclosed switch resistance box with 4 dials.

Enclosed switch resistance box with 4 dials going from 0 to 9 enclosed in a bakelite case. Top view.

Figure 2: Top view of the resistance box.

Enclosed switch resistance box with 4 dials going from 0 to 9 enclosed in a bakelite case. Front top center view.

Figure 3: Birds eye view of the resistance box.

The main application of the resistance box is to control the specific value of current to flow through the circuit. The advantage given by the resistance box is that the variable resistances are available at one point. If any circuit requires variable resistances, then there is no need of replacing the resistor.

This model of resistance boxes were suitable for commercial power frequency a-c as well as d-c. It comes with rotary switch decades. D-C resistance can be changed from zero setting; measured across binding posts, qual dial settings +/- 0.11 percent + 0.01 ohm. When highest decade in use is 0.1, 1.0, 10.0, 100.0, and 1000.0, the current rating is 1.6, 0.5, 0.16, 0.05 and 0.016 amperes respectively. It comes in a Molded bakelite case. Model number 4775-76.

The University of Kansas's Department of Physics & Astronomy currently have 13 of these in their possession. 1 is kept in the display case on the 2nd floor entrance of Malott Hall, while the rest are in storage.