This is the eight-channel answering device I made. The buzzer sounds when the answering button is pressed. But the sound of the buzzer is not a beep~, but a beep...beep. What is the reason? Can anyone teach?
Niki 發表於 July 8, 2020
Try adding a 1k resistor between the microcontroller and the transistor.
Aishwarya 發表於 July 8, 2020
No, even the sound is gone after the resistance is added. It should not be the problem of the driving circuit. This problem only occurs when the answer key is pressed, and it sounds okay for two consecutive seconds at the end of the answer time. And when pressing the answer key, sometimes it can beep continuously and sometimes intermittently.
Wilbur 發表於 July 8, 2020
Try adding a 470 resistor between the microcontroller and the transistor.
