From this picture we can see a complete circuit that contains battery, resistor, transistor,

capacitor, push button and speaker.

From the circuit, the voltage of the battery contain 12v flow from positive charge and separate to

push button 1(SW1), to resister 4(R4) and transistor 2(Q2). First current from Q2,it split to speaker, C2

and Q1. The current from R4 also flow to Q1.The current flow to resister 1(R1) from switch 1(SW1)

separate to resister 2(R2) and capacitor 1(C1). From resister 2(R2) the current separate to three part,

which are r3,q1 and c2. Likewise current flow from c1continue flow to three part, which are r3,q1 and

speaker. lastly so the current return to power source and the current keep flowing through circuit as

stated .