Yes, the given link by you :
http://info.hobbyengineering.com/specs/DIY-k15.pdf

After studying the circuit for a while, i have came to believe strongly that the buzzer circuit that i possess now is very very similiar to the one u mentioned if not identical. Now i believed that the "unknown customized IC(black lump of clay)" must be reponsible for the timer/oscillator and the transistor (a medium power transistor with hfe of 300+ and Ic rating of 1.5A) is in charge or toggling on and off the current through the autotransformer thus providing high voltage supplies to the terminal of the piezo diaphgram.

The only difference i can find between my buzzer circuit and the one shown in the website is that, the +Vcc is connected to pin 2 of the autotransformer (instead of pin 3 in website), and the collector of the transistor is connected to pin 1 (instead of pin 2 in website). I am not entirely sure what this means, but i certainly hope this will give a better idea of the type of buzzer circuit i am using here.

As for the current measurement, it has to wait until next Monday because i dont have the ammeter with me now, but for now i hope this helps!