How to Use: 1. Study the phenomenon of electromagnetic induction.Connect both ends of secondary coil B to the two terminals of the ammeter by wire.Quickly insert (or pull) secondary coil using one of the magnet to quickly insert (or pull) the indicator pointer is all deflected, indicating that the secondary coil has an inductive current.This phenomenon is called electromagnetic induction.Conversely, if the magnet is fixed, the auxiliary coil movement will also cause the same phenomenon. 2. Test the laws of rentz (1) Experiment method: Observe the change of current direction shown in the inspection meter when the magnet is inserted or pulled and when the polarity of the magnet.(2) Connect the original coil to a 3-4V DC power supply, place the single pole switch and 109 sliding leotat in line with the circuit.The same phenomenon will occur if you use the original coil instead of magnets to perform the above experiments.Changes the direction of the current flowing into the primary coil changes the direction of current directed to the secondary coil.(3) According to the picture (2) equipment, first insert the primary coil into the secondary coil, then connect to the primary coil.When the switch is turned on or off, the magnetic flux passing through a secondary diagram will change.This is also happen.The current is induced and the direction of the current is reversed.If you change the direction of the current flowing into the primary coil, you can change the direction of the current that is directed to the secondary coil.(4) According to the picture (2) equipment, insert the primary coil into the secondary coil to connect the circuit, then use the sliding leotat to quickly change the current strength (increase or decrease the current intensity), the secondary coil also generates induction current, and the direction of the induction current is the same as the figure (3).Combine the above experimentation results and analyzed them to validate the Law of Rentz.3. Put the primary coil of the device in the picture 2 above to study the phenomenon of magnetic induction into the secondary coil and wait to still.Secondary coil has no induction current.At this point, when the soft iron core C is inserted into the center hole of the primary coil, the soft iron core will magnetized, increasing and decreasing the magnetic field.The changes in the magnetic flux on the secondary coil also produce inductive current.This experiment can explain both magnetic induction and electromagnetic induction.While experimenting with device photos (2), a soft iron core is inserted into the center hole of the original line diagram for demonstration, the effect is more clearly increased by the current induced to the secondary coil.