Hi friends today i am going to show you how amplify the tone sound from um66/bt66 transistor with piezo buzzer. Its very simple by doing some modification to the buzzer. The buzzer already contains a npn transistor and a inductor which makes a high continuous beep sound.
And now we have to replace the boring beep with a melody tone by adding um66 to the buzzer.
Step 1: Need Parts and Peizo Connectoin.
Here red wire of peizo is positive and black is negative. Blue is zero.
Step 2: Actual Circuit Diagram
First Look into the actual buzzer circuit. This is the original circuit here emitter of npn connected to negative of the peizo and collector connected to the positive of peizo and the base connected to the zero wire of peizo. Now we have to completely remove the zero wire from the peizo. No need of connection and replace 220k with 1k.
Then move to next step.
Step 3: Modification of Circuit
Now pin one (out )of the um66 connect to the base of the npn.
Pin two (vcc) connect to the positive with the help of 1k resister and add a 3.3v zener diode to protect um66 from over voltage. Cathode connect to the base of npn and anode to the ground.
If the circuit not works replace the 1k resistor with a lower vale.
And now the project is complete.
U can use up to 3v to 9v.