Electronic – Normalized DC Current Gain (as oppossed to DC Current gain)

Now in order to get the collector current in mA, only a small amount of uA current is required

In one model of transistor operation, the base current controls the collector current. I'm concerned that you might be thinking that the base-current somehow creates collector current - it doesn't. You could think of it as the base current operating a valve that lets through collector current. All the current has to come (ultimately) from your power source.

using 0.15uF cap which gives upto 11mA currnt

Capacitors of a certain capacitance don't really have a specific current associated with them. There may be a maximum current they can safely deliver but that is likely to be a lot more than 11 mA for all but the tiniest capacitors. In essentially DC applications, the current flowing out of a capacitor depends on the voltage to which the capacitor has been charged, the resistance of the load and the current decays exponentially over time as the stored energy is release and the voltage drops.

The fundamental action of a bipolar junction transistor (BJT) is current gain. A small current passed through the base-emitter junction allows a greater current (maybe 100x) to pass between the collector and emitter.

But a BJT is essentially never used by itself, rather it is one component in a circuit, often an amplifier circuit.

By passing the greater collector-emitter current through a resistor, a voltage arises across the resistor. This voltage can be substantially greater in size than the input signal applied to the base of the transistor. So the circuit in which the BJT takes part can exhibit voltage gain.

There are other interpretations of BJTs as a voltage-controlled device (rather than current controlled), but that's for a later chapter.

As a first concept, the BJT is a current amplifier, which deployed in the appropriate circuit, can imbue that circuit with voltage gain, making it a voltage amplifier.