Here are the steps to take to make for a do-it-yourself homeowner to build their own ammeter at home. 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.
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.
The transistors are BC640, however you may try other transistors like 8550 or 187 etc. The proposed digital voltmeter, ammeter circuit module can be effectively used with a power supply for indicating the voltage and current consumption by the connected load through the attached modules.
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.
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.
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. 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.