Vibrator for a Spark Coil
If you do not have the time to make a vibrator or electrolytic interrupter for a spark coil, a common electric door-bell makes a good substitute. Connect one of the primary wires to the binding-post of the bell that is not insulated from the frame, and the other primary wire to the adjusting screw on the make-and-break contact of the bell, as shown in the sketch. The connections are made from the batteries to the bell in the usual manner.—Contributed by Ralph Tarshis, Brooklyn, N. Y.
Bell Used as Vibrator