普天主要生产应用于高压领域的继电器，它与普通继电器的最大区别在于普天的继电器采用了独特的陶瓷真空密封技术，将继电器的接触点密封，与外界空气隔离以获得高的耐压。在密封空间中按照不同的继电器使用要求而采用不同的介质。目前普天生产的继电器主要采用两种不同的介质，一种是真空介质，另一种是高压气体介质。Chapter 1 Putian`s high voltage relaysPutian provides relays for High voltage applications,which are notablely diffent from general relays by using particular impervious Ceramic technology to keep relays contacts in sealed container that is separate from air and obtain high dielectric strengths.The envelope of relays can be filled with different medium for different applications. Two kinds of medium ,vacuum and high pressure gas,are normally used in putian`s relay.真空介质的特点：由于在真空中只有非常少的气体分子，这使得真空中不容易产生电弧。在理想的状态下，真空有可能达到每0.1毫米10000V的介电强度。另外，由于没有空气的存在，真空中触点不会氧化，因此真空型继电器的接触电阻较小而且较稳定。特别适合应用与射频场合。Performance of Vacuum:As very few gas molecule exists in vacuum,arc hardly occurs.Ideally ,it is possible to obtain dielectric strengths of 10000V per 0.1mm in vacuum.Because there is no air in vacuum,contacts are oidation free.Thus,vacuum relays typically have low and stable contact resistance,which is ideally used in radio frequency condition.高压气体介质的特点：纯净的高压气体介质能使继电器保持良好的耐压并保护触点不被氧化，它在继电器进行热开关时可以避免触点高温烧损。这种继电器用于ESD测试设备、电缆测试设备和心脏起搏器，是理想的电容器快速充电或放电的开关元件。在对电流波动很敏感的应用中，充气继电器具有低而稳定的泄漏电流，特别是在断开触点间，可以长时间保持很低的泄漏电流。Performance of high pressure gas:Pure high pressure gas allows relays to obtain advanced dielectric strength and avoids oxidation .When relays are used for hot switching,gas can keep contacts from hig temperature burning.These relays are ideal for high in-rush capacitive make and capacitive discharge loads found in ESD test equipment,cable test equipment and heart defibrillators.Gas-filled relays also provide low,stable leakage current in applications sensitive to current fluctuations especially across open contact sets over long periods of time.