1
\$\begingroup\$

According to my understanding the common collector transistor should be like figure-1 but in book it is given as figure-2 and in it Vcc is enter image description heregiven.Can anyone provide me proper explanation of this.

\$\endgroup\$
0
\$\begingroup\$

(1) Shows Rb is negatively biased less than collector

(2) Shows Rb is biased above ground such that Vbe>0.6 to be active
so (2) is more general purpose

Although are Thevanin equivalents, (1) is unconventional with notation and both lack a 0V symbol. (gnd) Vcc refers to positive (Collector), Vee refers to -ve (emitter) usually gnd.

\$\endgroup\$
0
\$\begingroup\$

The two circuits are very similar. The only difference is your point-of-view. In circuit 1, the "ground" reference point is at the top. In circuit 2, the "ground" reference point is at the bottom.
Circuit 2 is the one you'll see most often in circuit diagrams.

schematic

simulate this circuit – Schematic created using CircuitLab
In left diagram Vbb1 < Vee1.
In right diagram Vbb2 < Vcc2.

\$\endgroup\$
  • 2
    \$\begingroup\$ Your left battery in the left schematic is flipped. \$\endgroup\$ – Janka Mar 13 '18 at 20:57
  • \$\begingroup\$ @Janka Honestly, hadn't noticed. But now that you mentioned it, the OP diagram Vbb in figure 1 has a wrong polarity, at least for conventional NPN transistor biasing. \$\endgroup\$ – glen_geek Mar 13 '18 at 21:01
  • 1
    \$\begingroup\$ The way you have it now, the base current is negative. \$\endgroup\$ – Janka Mar 13 '18 at 21:03
0
\$\begingroup\$

Figure (1) is the common collector circuit and the figure (2) is common emitter circuit which is employed widely among the three types of transistor configuration. Both of them above lacks a ground (0V) connection in it. That textbook has mentioned it incorrectly.

enter image description here

The common collector configuration is similar to that of the common emitter configuration, with the expectation that the load resistance is in the emitter circuit rather than in the collector circuit and the output is taken from emitter lead instead of the collector.

Here is the common emitter configuration

enter image description here

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.