use of transistor as current amplifier

engineers,would any one brief me how a transistor is used as a current amplifier when we have both fixed base voltage and current,the explanation should clarify how the Vcc(supply voltage for active devices) gets involved and hence amplification methodolgy....forwarding my appreciations

There's more than one kind of transistor, but I'm going to assume you mean Bipolar Junction Transistor or BJT. The BJT is inherently a current amplifier. The current that flows from the base to the emitter controls a current flowing from the collector to the emitter by a factor of Beta or Hfe -- i.e. Ic = β*Ib where Ic is the current flowing from the collector to the emitter, and Ib is the current flowing from the base to the emitter and β is the Beta or Hfe of the transistor (not a constant -- see datasheet for transistor in question). This is true as long as the transistor is not either in cutoff or in saturation.

If you want a circuit that provides pure current amplification, then Google "emitter follower transistor circuit" or "common collector transistor circuit". The common emitter circuit can also function as a current amplifier if the load is put in series with the collector (i.e. in place of the collector resistor).

Not sure if that is what you were after, so if not, ask again with more detail.

BTW, I see that you put this question under the "Electromechanical" category. A transistor is not electromechanical.