Merits and Demerits of Collector-to-base bias:

Merits:

In this type of circuit the circuit stabilizes the operating point against differences in temperature and β (that is replacement of transistor)

Demerits:

In this type of circuit, to keep I_c independent of β, the subsequent condition must be met:

I_c = βI_b = β(V_cc - V_be)/ R_b + R_c + βR_c ≈ (V_cc - V_be) / R_c

This is the case while

βR_c >> R_b

As β-value is set (and usually not known) for a given transistor, this relation can be satisfied either through keeping R_c fairly large or making R_b very low.

If R_c is large, a high V_cc is essential that increases cost also precautions are essential while handling.

The reverse bias of the collector-base region is small If R_b is low that limits the range of collector voltage swing which leaves the transistor in active mode.

The resistor R_b causes an AC feedback, decreasing the voltage gain of the amplifier. This not desirable effect is a trade-off for greater Q-point stability.