The switch, E, is arranged so that each step cuts in or out five turns. The contacts on this switch are numbered in the reverse direction. The fifth contact of switch D, and the fifth contact of switch E, are connected together. The fourth contact is connected to the fifth tap, the third contact to the sixth tap, the second contact to the seventh, and the first contact to the end of the winding.
This arrangement makes it possible to secure any voltage from one-half to ten in one-half-volt steps from the secondary of the machine. Each step on the switch, D, will give two volts, while those on E will each give one-half of a volt.
Fig. 189.—The Complete Switch.
Two binding-posts (marked P and P in the drawing) mounted in the upper corners of the base are connected to the terminals of the primary winding. The two posts in the lower corners (marked S and S in the drawing) are connected to the switch levers, and are the posts from which the secondary or low voltage is obtained.
Fig. 190.—Diagram of Connections.
The transformer may be connected to the 110-V. alternating current circuit by means of an attachment plug and cord. One end of the cord is placed in each of the primary binding-posts. The other end of the cord is connected to the attachment plug so that the latter may be screwed into any convenient electric-light socket.
Fig. 191.—Top View of the Transformer.