- To demonstrate the characteristics of electromagnets.
The air coil (solenoid) is clamped and mounted at an angle of about 45 . The "LD-DC" power supply is connected to the coil and current is adjusted to about 2.5 A.D.C. The various core materials are inserted. The iron core will be restrained from falling out by magnetic forces. All cores can be tested for magnetic properties by touching nails etc. to them. When power is switched off, even the iron core slips out, by gravity.
Do not use too high a D.C. current for "too long," as the plastic core will soften by heat and will not be straight.