How can we distinguish between active buzzer and passive buzzer?
1. Through appearance: the welding foot of the buzzer can be turned upward. If the circuit board is black epoxy, if the circuit board is green, it means passive;
2. Test: adjust the multimeter to Ohm gear. If the resistance value is displayed, it is a passive buzzer. If it makes a continuous sound, it is an active buzzer.
3. Directly connected to the DC power supply, those who will make sound are active, and those who will not make sound are passive.
