How to Build Your Own Ammeter
An ammeter is used to measure the amount of electrical current that is moving through a particular circuit. They have been used for many years through the use of wire coils and a magnetic field. Buying a multipurpose tester will also perform the same functions, but may be out of your budget or not available where you are. You can easily make your own ammeter with easy to find items. Here are the steps to take to make for a do-it-yourself homeowner to build their own ammeter at home.
Step 1 - Cut Tube and Wind Coil
Once you have all the materials assembled you can begin to build your own ammeter. Start by winding the magnetic wire around the toilet paper tube. You will want to make sure that there is at least 100 coils around it. They should be tightly wound around the tube without crushing it. Leave about 0.5-inches of wire sticking from each end.
Step 2 - Set Tube on Stand
Place the tube on top of a piece of cardboard and secure it with hot glue. Remove the ends of the magnetic wire with a piece of sandpaper to expose the wire inside the insulation. You do not want to cut the insulation of the wire off as you many nick the wire within the insulation. This will result in the ammeter not working properly.
Step 3 - Put Loop in Wire
Take an end of the magnetic wire and form a loop in it. You will need to twist the end several times. Make a small square with the aluminum foil and wrap it around the end that you just formed the loop in it. Secure it to the cardboard base with a small thumbtack. Repeat this process of placing aluminum foil over the loop in the wire with the other end of the wire and mark it with an '+' for positive.
Step 4 - Tie Magnets
Cut small slits into the toilet paper tube near the wires. Place 2 magnetic discs on the thread on the inside of the tube and suspend them in the middle of the tube. Tie off the thread on the outside of the tube. The thread should have enough slack in it the thread so that the discs do not touch each other.
Step 5 - Rotate Assembly
Now that you have the magnets in place you should rotate the whole assembly so that you can only see the very edges of the discs. This means the ammeter is at zero.
Step 6 - Connect Wires
Now that you have the ammeter built you need to try it out. Take the positive end of a battery and connect it to the wire that you labeled as the positive wire. Take the negative end of the battery and connect it to the negative end of the magnetic wire. Once the 2 connections are made you should see the magnetic discs inside the tube spinning. If this happens, then you will know that there is current running through your ammeter.