The wire from the primary-coil which is as yet not connected should be attached to nail G, and one battery wire should be connected to a binding-post plate I fastened to the lower end of strip F. [Figure 198] shows how the binding-post plate is made out of a doubled piece of tin, with a hole punched through it for a small binding-screw.
This completes the interrupter. Mount it beside the induction-coil upon the base block, and connect it with the battery and the induction-coil, as shown in [Fig. 187]. Connect the battery cells in series. Two cells will be enough.
Figs. 195-198.—Details of Interrupter.
How the Interrupter Works. When you turn the crank of the interrupter, each nail in spool E raises the end of strip F, in passing it, thus breaking the electrical contact between it and the head of nail G. If the strip has been bent properly, it will spring back into contact with the head of nail G, and each time the contact is made, the person holding the handles will receive a shock. The strength of the current can be regulated somewhat by the speed with which the interrupter crank is turned. The shocks are stronger and more distinct when the crank is turned slowly.
Home-made electrical toys of a light construction are easily operated by a toy motor, when the motor and battery cell are not carried by the toy; but when both are transported, as in the case of a wagon, the construction must be very carefully worked out, or the motor will not be powerful enough to drive the wheels.
