To turn this into a more precise "Tangent Galvanometer," you can follow advanced designs from National MagLab which use a vertical coil and the Tangent Law to calculate absolute current values.
: Approximately 3–4 feet of thin (24-gauge or smaller) wire. Magnetic Compass : Standard handheld variety. Power Source : A 1.5V C-cell or D-cell battery. Wire Strippers : To remove insulation from the ends. Tape : To secure the wire in place. 2. Prepare the Wire how to make a galvanometer
Carefully slide the coil off the former. Use tape or glue to hold its shape. Mount the coil vertically on the base so its center is open. To turn this into a more precise "Tangent
Attach the two free wire ends to brass screws or binding posts fixed to the base. These will be your positive (+) and negative (−) input terminals. Power Source : A 1
: To secure the components (optional). Electrical Tape : To hold the wire coils in place. Step-by-Step Construction Guide 1. Prepare the Magnetic Compass
: More turns (wraps) around the compass will make the device more sensitive to smaller currents. 4. Testing the Device How to Make & Use a Galvanometer - Home Science Tools
Place the compass (or your magnetized needle) in the of the coil.