IS Emitter base resistance greater than emitter collector resistance in transistor?
It depends on whether the transistor is in the active region or
not. Usually, the transistor would be in the active region when we
are asking this question. if we look at the data sheet for the
popular 2N3905 transistor, available at
http://www.fairchildsemi.com/ds/2N/2N3905.pdf,
we see that if V collector-emitter is 10 V, the collector
current is 1 mA, and the small signal frequency is 1 kHz, the
typical small signal signal input impedance (which is nearly the
same as small signal base-emitter resistance) is about 5,000 ohms.
Under the same conditions, the typical output admittance, (which is
nearly the same as the small signal collector-emitter resistance)
is about 30 microsiemens. Calculate 1/0.000030 to find that this is
the same as about 33,000 ohms, so in this case the
collector-emitter small signal resistance is greater than the
base-emitter small signal resistance. You might be able to find an
operating point where the reverse is true.