The input signal goes to the (+) input of the amplifier.
The opamp is a low power device so the transistor is added to increase output current.
...Example: The opamp can output +10 to-10mA. The transistor can output 0 to +100mA. It can not pull down. (made up numbers)
The output of the transistor is about 0.6 volts below the input of the transistor.
The opamp is looking at the input signal and the output of the transistor. The opamp will move its output so that the emitter of the transistor is at the exact same voltage as the input signal.
so; the voltage gain is 1. The input current is about 0A. The output current (depending on the resistors) could be 100mA or 200mA max.
I don't know that parts you have so there is some made up numbers.
So what u r saying is that this circuit is just a buffer with a current amp ?
BTW, the res values are, from left to right: 100Ohm, 100Ohm, 100Ohm,10kOhm
What does the 100Ω on the non-inverting input do? If it were to be useful for some sort of overload protection, it would have to have a resistance of >1K...