Page:Popular Science Monthly Volume 88.djvu/817

 Popular Science Monthly

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��the brass ferrules around the hole (Fig. i), apply a small amount of solder to each. Assemble the fuse by slipping the copper wire through the hole; then apply solder and mend with a hot iron. Fit the fuse in the fiber and in the hole in the opposite brass ferrule. Tin in the same way as before and cut the copper wires flush with the brass end, as in Fig. 2. The fuse will then be found to be as serviceable as before.

Substituting a Flashlight for a Door- Bell

'HEN there is sickness in the house, it is often necessary to avoid all noise as far as possible. At such times the door- bell is a source of great annoyance. To overcome this difficulty, disconnect the wires from the bell and run them down the gas or electric fixtures. Leave the ends bare and bend them into hooks, as shown in the diagram. Secure a flash- light bulb and solder two wires to it, bent as shown. The flashlight can then be connected with the push-button at the door by simply hooking it on to the wires.

This arrangement is also of great service to anyone who is deaf. If wires are arranged in every room, the flash- light can be attached in whichever room the deaf person happens to be. Thus a bell is not needed. — J. K. Noble.

Telephone-Line Test- Clips Easily Made

NY telephone

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��man can make a pair of line test- clips for ten cents. F?uy two large safety-pins and cut j^ in. off the point of each. Solder a piece of No. 6 cop- per wire, i3^ ins. long to the part from which the {)oint was cut so

that it will pass between the wires at

the open end of the pin.

File a small groove in the copper in

���which the line wire may rest. Then simply solder the test cord to the loop at the other end of the pin.

Changing a Telegraph Sounder Into a Relay

A TELEGRAPH sounder can easily be changed into a relay by add- ing a small piece of copper as shown in the accompanying diagram. A piece of sheet copper is bent as shown and placed under the screw C, but previous to this, a piece of thin mica is placed between screw C and stand E at D. A piece of small wire is coiled and carried from the screw B to the screw C, to insure a good contact.

The two telegraph wires are attached to the regular binding posts and the; relay wires are connected with screw B and copper A. When the magnet's base is drawn down, the arm F completes, the circuit in B and A. — Wm. Harrier.

A Current Reverser for Small Motors

A DOUBLE-POLE, double -throw switch, if connected according to the accompanying diagram, will reverse the direction of a direct-current motor. Disconnect the wires on the motor that are connected to the binding posts, brushes and field. Connect binding post No. I of the switch and No. 6 post to one end of the field. Connect the other field terminal to posts No. 2. and No. 5. One brush is connected to one binding post of the motor and No. 3 post of the switch. The other brush is connected to No. 4 post. The batteries are inserted between one of the binding posts on the motor and No. 3 post of the switch.

���Diagram of current reverser for small motors

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