TKANSISTOKS AND JUNCTION DIODES 



835 



tluiii 0.01 per {'(Mit per de<>;ree C The specific applications covcM'ed later 

 ill this discussion show methods to compensate lor slope and temperature 

 variation when necessary. 



2.3. Junction 'J'ransii<l(>r Action 

 2.31. Tiro-Rectijicr Anah/sis 



In junction transistors tiiere are two p-n junction rectiliers contained 

 in the semiconductor material. Of the materials now in use germanium 

 is the more pre\'alent. llememl)ering the results of adding donor and ac- 

 ceptor impurities to obtain n and p type materials covered in section 2.1 

 these two rectifiers are obtained by interposing a layer of p type material 

 between two layers of n type making an 7i-p-n transistor or interposing 

 a la^'er of n tj^pe material between two layers of p type making a p-n-p 

 t7-ansistor. The electrical connections are designated as the collector 

 terminal, the emitter terminal and the base terminal. Both types of 

 transistors (n-p-n and p-n-p) have a rectifying junction between the 

 collector and base terminals and another rectifying junction between the 

 emitter and base terminals. The polarity of the collector and emitter 

 rectifying junctions determines whether the transistor is n-p-n or p-n-p. 



Figs. 7(a) and 7(b) are simplified diagrams illustrating respectively 

 the internal circuits of n-p-n and p-n-p transistors. The figures show the 

 characterizations of transistors by means of a two-rectifier analogy. 

 Although a transistor may be somewhat over-simplified by this method 

 of characterization, the analogy permits the power engineer to approxi- 

 mate the operation of transistors in familiar terms. Experience in the 

 development of the circuits described later in this article has proven that 

 the analogy is valid under circumstances where the operation of the 

 transistor as a dc amplifier is of interest. 



26 



25 



z24 



23 



22 



Fig, 



1 23456789 10 



REVERSE CURRENT IN MILLIAMPERES 



6 — Saturation voltage characteristics of a reference voH-age diode. 



