Description

Elongated box with two parallel rows of 13 connections. Partial label from MIT Electrical Engineering Department.

Decade boxes are pieces of test equipment that are used to check and calibrate test equipment. They are often used while building electrical circuits in order to switch out the values of different components for resistance, capacitance, and inductance. This instrument is a capacitance box, so users could incrementally adjust the capacitance in an electrical circuit in-circuit without the use of an outside power source.