1. External heating electric soldering iron

2. Components
The soldering iron core is a key component of an electric soldering iron. The electric heating wire is wound parallel on a hollow ceramic tube, with a mica insulation in the middle and two wires connected to a 220V AC power supply.

3. Product specifications
There are many specifications for externally heated electric soldering irons, with commonly used specifications including 25W, 45W, 75W, 100W, etc. The higher the power, the higher the temperature of the soldering iron head.

The internal resistance of a soldering iron core varies depending on its power specifications. The resistance value of a 25W soldering iron is about 2k Ω, the resistance value of a 45W soldering iron is about 1k Ω, the resistance value of a 75W soldering iron is about 0.6k Ω, and the resistance value of a 100W soldering iron is about 0.5k Ω.

4. Using materials