Buzzer YL-44 is getting very hot when IDLE on my ESP32 CAM

[zimbo86]

Hi all,
i built an doorbell with ESP32 CAM and got an issue with this buzzer;
YL44 Buzzer

As I cant use "tone" on ESP32 this is the (simplified) code that generates the tone:

// BUZZER CONFIG
int pin_buzzer = 1;
const int channel = 15;
const int frequency = 2000;
const int resolutionBits = 12;

void setup() {
  pinMode(pin_buzzer, OUTPUT);
  ledcSetup(channel, frequency, resolutionBits); // BUZZER
  ledcAttachPin(pin_buzzer, channel); // BUZZER
}

void toneSIMPLE() {
      ledcWriteTone(channel, 783);
      delay(500); 
      ledcWriteTone(channel, 0);
      delay(20);
      ledcWriteTone(channel, 659);
      delay(500);
      ledcWriteTone(channel, 0);
}

.. in loop function toneSimple is called when ring button is pressed.
My issue is, that the buzzer is getting very hot when its idle. A simple thermometer shows about 55°C on the surface constantly.

This was my first project with a PCB, here is the layout:

Any thought on this?
What am I doing wrong?
Any help is much appreciated

[Railroader]

Link to buzzer datasheet please.

[zimbo86]

actually no datasheet available.
Heres a schematic:

I read in another post, that HIGH will turn the buzzer of. So i tried:

void toneOK() { 
digitalWrite (pin_buzzer, LOW); // Turn Buzzer ON
delay (2) ;
ledcWriteTone(channel, 1046); 
delay(150); 
ledcWriteTone(channel, 0); 
digitalWrite (pin_buzzer, HIGH); // Turn Buzzer OFF
} 

but still above 50 degrees on surface when idle

[Railroader]

If Vcc of the controller is 5 volt this would work. If controller Vcc is 3.3 volt it will not shut off the transistor.
Measure the voltages at the transistor base. Measure the voltage across the buzzer.