1, look at the switch housing material. Main switch brands on the market generally used PC, PC again called bulletproof plastic, impact resistance, high temperature resistance, difficult to change characteristics are important for the control of electrical switches. Better switch the front panel and the back of the base is made of PC and switch on the base with a black nylon material replaces the PC material, so that costs can be much lower
2, the second contact, conductive parts is in the process of switching points of contact. Contact depends on the size (bigger is better), depends on the material. Contacts there are three kinds of silver-nickel alloy alloys, cadmium, silver and sterling silver. Silver-nickel alloy is the ideal contact materials, electrical conductivity, hardness, good, not easily rust. Silver-cadmium alloy contacts other aspects are also good, but elements are metals is cadmium, harmful to the human body on the one hand, on the other hand and silver Fusion is also not ideal, cadmium metal particles on the surface in contact, conductive may pull the arc. Pure silver contacts are not suitable conductivity good, but silver soft texture, are easily oxidized (like silver jewelry for a long time will turn black). Soft, switch the contact deformation of the oxide conductivity of rust will be a lot worse, rust is also easy to heat, it is easy to burn the contacts.
3, the third structure. Now, mainly large-Panel, look-and-feel all thumbs were better than before. -Thumb's biggest problem is easy to get stuck, because the torque is shorter, switching range is small, spring-soft or hard, and could cause switch got stuck. A couple of days ago (don't tell me it's the u, if u then I am a Martian) out of a so-called reset switch, try feel critical dry, take a look inside is a small wheel, click the turn 1/4 to reduce the inevitable friction coated with lubricant. Just six months after oil dried up, how to use this switch.