The structure of the soldering iron
There are two types of electric soldering irons: external heating type and internal heating type:
The external heating electric soldering iron is composed of a soldering iron tip, a soldering iron core, a shell, a wooden handle, a power lead, a plug and other parts. Because the soldering iron head is installed inside the soldering iron core, it is called an external heating type electric soldering iron. The soldering iron core is the key part of the electric soldering iron. It is formed by winding the heating wire in parallel on a hollow porcelain tube. The mica sheet in the middle is insulated, and two wires are drawn out to connect with the 220V AC power supply. There are many specifications of external heating electric soldering irons, commonly used are 25W, 45W, 75W, 100W, etc. The higher the power, the higher the temperature of the soldering iron tip.
The internal heating electric soldering iron is composed of a handle, a connecting rod, a spring clip, a soldering iron core, and a soldering iron tip. Because the soldering iron core is installed inside the soldering iron head, it heats up quickly and has a high heat utilization rate. Therefore, it is called an internal heating type electric soldering iron. The commonly used specifications of internal heating electric soldering iron are 20W and 50W. Due to its high thermal efficiency, a 20W internal heating soldering iron is equivalent to a 40W external heating soldering iron. The rear end of the internal heating type electric soldering iron is hollow, used to be sleeved on the connecting rod, and fixed with a spring clip. When the soldering iron tip needs to be replaced, the spring clip must be withdrawn first, and the front end of the soldering iron tip should be clamped with pliers. Pull it out slowly, remember not to use too much force, so as not to damage the connecting rod.
