A
feedthrough capacitor not packaged by glass and applicable to an airtight device includes a disk-like
ceramic capacitor body (1) of a multilayer laminated structure. A
Kovar tube (3) is disposed in an inner hole (2) of the disk-like
ceramic capacitor body (1), a conductive pin (4) penetrates through an inner hole (2) of the
Kovar tube (3), and the conductive pin (4) and the
Kovar tube (3) as well as the Kovar tube (3) and the disk-like
ceramic capacitor body (1) are soldered and fixed with gold-
tin alloy solder. The distance between the conductive pin (4) and the inner hole (2) of the disk-like
ceramic capacitor body (1) is shortened by adding the Kovar tube (3) between the conductive pin (4) and the disk-like
ceramic capacitor body (1), so that the amount of the gold-
tin alloy solder used in a
soldering process is effectively reduced. Because the amount of the gold-
tin alloy solder used is reduced, the influence of
thermal expansion and contraction of the gold-tin alloy solder on a
ceramic capacitor can be greatly relieved, thereby improving the quality of the ceramic capacitor. Moreover, the entire product can be easily cleaned, with no flux left, and dense solder joints are formed to meet specific airtightness requirements.