Heating problem

I was trying to make a coil with a insulated wire but when i touched the cable ends to 1.5 V battery it instantly heated (where the cable ends touched to battery ) and hurt me. Why ( or How )did this happen?

Too much current... Combined with either a poor (low resistance) connection along with the low-resistance of the wire, or the internal battery resistance. Low resistance (high current) will also reduce battery life.

You may need to research the ohms-per-foot (or per-meter) for the wire you're using, and either use more wire or thinner wire for more resistance.*

[u]Ohm's Law[/u]: Current = Voltage/Resistance. You'll need at least a couple of Ohms to keep current below 1 Amp.

Power (related to heat) is Voltage x Current.

NOTE: You'll also get a momentary high voltage "kick" ([u]Back EMF[/u] when you disconnect it which can cause a spark or shock you (if you're touching it) when you disconnect the coil from the battery.

  • We normally use copper wire because it has low (near zero) resistance, but there is normally resistance somewhere else in the circuit to limit the current.

What length of what gauge of wire? Electromagnets are normally made with hundreds of turns of fine magnet wire (30 AWG or less) to provide a lot of resistance. If you use a short length of large gauge wire, yeah thing’s heat up pretty badly.

I get it , thanks :slight_smile: I think, i will use a resistor becuase my coil is gonna be very small, i have only 10 meter coil wire.