Transistor Basics is a free introductory textbook on transistors and their basic applications. See the editorial for more information.... 
Home Grounded Emitter and Grounded Collector Transistors The Grounded Collector Connection Power Gain  
Search the VIAS Library  Index  
Power Gain in the Grounded Collector ConnectionAuthor: Leonard Krugman The operating power gain as defined by equation 346 is:
In terms of the internal transistor parameters for the grounded collector connection, the voltage gain becomes:
(R_{g} + r_{11}) (R_{L} + r_{22})  r_{12}r_{21} > 0 Substituting the numerical values of the typical pointcontact transistor into this equation: (R_{g} + 12,000) (R_{L}  11,850) + 12,000 (11,900) > 0 The conditional stability characteristic is plotted in Fig. 414. Fig. 414. Conditional stability characteristic (grounded collector). The grounded collector circuit can be stabilized by adding an external resistance R_{c}. in the collector arm. For example, assume that a resistor R_{c} = 3,100 ohms is placed in series with r_{c}. The opencircuit parameters now become:
The conditional equation now becomes: (R_{g} + 15,100) (R_{L}  8,750) + 8,900 (15,000) > 0. This stabilized conditional stability line is also plotted on Fig. 414. The maximum available gain, defined by equation 355 can be applied to junction transistors, since the stability factor is not greater than one. In the grounded collector connection, since δ is always very near unity, this equation can be simplified as:
Notice that this result is nothing more than the product of the maximum voltage gain  and the maximum current gain  .The maximum available gain in terms of the transistor internal parameters is:
For the typicaljunction transistor


Home Grounded Emitter and Grounded Collector Transistors The Grounded Collector Connection Power Gain 