The paper must be about one-half inch larger all the way around, so as to leave a good margin. The alternate sheets of tinfoil, that is, all on one side and all on the other, are connected.
The condenser is connected directly across the terminals of the interrupter.
Fig. 165.—Condenser.
There are various methods of mounting a coil, the most common being to place it in a box with the interrupter at one end. Perhaps, however, one of the neatest and also the simplest methods is to mount it in the manner shown in the illustration.
The end-pieces are cut out of wood. No specific dimensions can be given, because the diameter of the coils will vary somewhat according to who winds them and how tightly they are made. The coil is enclosed in a tube made by rolling up a strip of cardboard and then giving it a coat of shellac. The tube may be covered by a strip of black cloth, so as to improve its appearance.
Fig. 166.—Completed Coil.
The vibrator is mounted on the end. The core projects through a hole in the wood near the end of the vibrator spring so that the latter will be drawn in by the magnetism of the core when the current flows. The condenser may be placed in the hollow box which forms the base of the coil.
The secondary terminals of the coil are mounted on a small strip of wood bridging the two coil ends.