通信用SMD型PTC热敏电阻的研制

Preparation of SMD PTC Thermistor for Telecommunication Equipment

论述了程控交换机二级保护用SMD型PTC热敏电阻的研制.重点研究了在原二元基多重掺杂的基础上添加石墨材料,考察其耐电流能力;同时研究了不同烧结温度及温升对耐压能力的影响.实验表明:添加1%～5%的石墨,产生了少量气孔,能有效提高耐电流冲击能力;在1 320～1 350℃范围内,烧结温度越高,元件的耐压能力越高;温升速度为350～450℃/h时,耐电流能力增强.

Investigated were the technics of the development and production for SMD PTC thermistor which used for line protection in digital switching system. Graphite was added into the original dual-composition and the capability of anti-over-current was also examined. Effects of different sintering temperature and temperature increasing speed on the capability of anti-over-voltage were also studied. Experimental results show that suitable amount of air holes will occur if 1%~5% of graphite is added. They lead to increasing shock capability of anti-over-current. With increasing sintering temperature, the capability of anti-over-voltage will increase in 1 320~1 350℃. The capability of anti-over-current is improved when temperature increasing speed is 350~450℃/h.