DIFFUSED p-n JUNCTION SILICON RECTIFIERS 683 



silicon rectifiers. It is possible to use these devices in parallel if oni' ad- 

 justs the lead resistances such that no one unit will be allowed to con- 

 duct much more than its share of the current. 



7.5 As a conclusion to this section, it should be noted that these rec- 

 tifiers are expected to have a long life when operated within their rat- 

 ings. They are able to operate for short periods of time (seconds) at five 

 times their rated currents. Since the rectifiers have an extremely small 

 series resistance, they should be protected against accidental surges 

 and turning on to a capacitance input filter. 



8.0 SUMMARY 



8.1 The development rectifiers described in the article are silicon 

 diffused p-n junction rectifiers. These devices together with associated 

 cooling fins can be used to rectify a complete range of currents from 

 to 50 amperes in a single phase, half wave rectifier circuit. They can be 

 used in more complex rectification circuits to yield even more dc cur- 

 rent. Also, they are able to withstand at least 200 volts peak in the in- 

 verse direction and operate satisfactorily at temperatures as high as 

 200°C. Furthermore, one process of diffusion and plating is sufficient 

 for all the devices of the class. This makes it possible for one diffusion 

 and plating line to feed material for all the rectifiers in a manufacturing 

 operation. 



8.2 The rectifiers discussed behave according to the theory of semi- 

 conductor devices which makes it possible to design them for given 

 electrical, thermal, and mechanical characteristics. One failure to meet 

 ideal theory of a p-n junction is with the forward characteristic. 



8.3 The diffused silicon type of rectifier has been compared with 

 germanium and selenium units and has better reverse characteristics 

 at all temperatures. In the forward direction, the germanium units have 

 a smaller voltage drop for any given current than the silicon rectifiers 

 but the silicon devices are capable of operating at much higher tem- 

 peratures, thereby permitting higher overall current densities than the 

 germanium devices. 



8.4 The diffused silicon rectifiers are capable of use in any rectifier 

 application where dc currents up to the order of 100 amperes are re- 

 fjuired and where inverse peak voltages up to 200 volts are encountered. 

 Another imoortant use for these devices will be in the magnetic ampli- 

 fier application where the low reverse currents of silicon will enable 

 large amplification factors to be realized. Since the forward character- 

 istics of these devices are so uniform, they can be used in voltage ref- 

 erence circuits that require voltages near 0.6 volts and in circuits uti- 



