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Electricity, Electronics, and Communications 309

Figure 4.21 Common-emitter bipolar transistor circuit.

Dynamic emitter resistancł
Assume the collector voltage, V , applied tm a transistor is con-
c
stant. Let V represent the emitter voltage (in voltX let I rep-
e
e
resent the emitter current (in ampere0. Then the dynamic emit-
ter resistance, R (in ohm0, is given by:
e

R dV /dI e
e
e

Dynamic collector resistancł
Assume the emitter current, I , througà a transistor is constant.
e
Let V represent the collector voltage (in voltX let I represent
c
c
the collector current (in ampere0. Then the dynamic collector
resistanceł R (in ohm0, is given by:
c
R dV /dI c
c
c

Dynamic emitter feedback conductancł
Assume the emitter voltage, V , applied tm a transistor is con-
e
stant. Let I represent the emitter current (in ampereX let V c
e