With Vacuum & Tube Counterparts
| The transistors of primary interest to the | exclusively for most amplification purposes | |||||
| radio engineer and service technician are the PNP and NPN Junction types, whose transistor actions are identically alike, ex- cept that symbolically, the emitter arrow points towards the base in the PNP and away from the base in the NPN. The common-emitter circuits are used almost |
as are the common or grounded-cathode vacuum tube circuits. The common-base and common-grid as well as common- collector common-plate circuits are used more for special applications such as impedance matching to and from audio transmission lines, etc. |
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| PNP CONTIGURATIONS | NPN CONTIGURATIONS | VACUUM-TUBE CONTIGURATIONS |
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| Common emitter–Common cathode. | ||
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| Common base–Common grid. | ||
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| Common collector–Common plate. | ||
