How To Test The Parameters Of Electromagnetic Passive Buzzer

The method of electromagnetic passive buzzer to test the parameters is introduced as follows:
1. Refer to the standard test circuit of the electromagnetic passive buzzer in Figure 1 to make a test amplifier, and the transistor 2SC3199 in the figure can also be replaced by domestic transistor 9014;
2. Prepare necessary test instruments and equipment (function signal generator, stabilized power supply, sound pressure meter, multimeter, test frame); These are the more professional equipment for buzzer testing, and if the user uses a single buzzer, it can also be used
Simpler devices instead.
3. Refer to Figure 2 to connect the instruments and equipment used correctly; If possible, make a fixed test frame, test frame production requirements: there should be no obvious obstacles within 40cm around the buzzer.
4. Set the correct parameters of each instrument
Function signal generator: select the output waveform as a square wave; Select the duty cycle of the square wave as 50%; Adjust the amplitude of the output waveform to be more than 5Vp-p, if there is no voltage display on the instrument, it can be verified by a multimeter; Adjust the output frequency to the rated frequency to be used for this buzzer.
Power supply: Adjust the output voltage of the regulated power supply to the rated voltage used by the buzzer, and verify it with a multimeter.
Sound pressure meter: Because the microphone of the sound pressure meter is relatively precise and affected by the environment, it is best to use a calibrator to calibrate before each use; Then jump to the test range that the buzzer is suitable for, and some sound pressure gauges do not need to adjust gears.
Ammeter: replace with a multimeter, connect in series in the circuit, adjust to the DC200mA gear (part of the multimeter test current when the internal resistance is large, will affect the normal operation of the buzzer, in this case, please test the SPL value do not connect the ammeter, after the SPL test and then test the current consumption separately)
5. Connect the buzzers one by one to test, read out the corresponding SPL value and consumption current, note: the electromagnetic buzzer has positive and negative polarity, do not connect the reverse.
6. Test of buzzer impedance: The impedance value of the electromagnetic buzzer usually indicates the DC resistance value of the coil, so we only need to adjust the multimeter to the corresponding resistance gear and connect the two poles of the buzzer.
The test method of the above electromagnetic passive buzzer is a relatively unified simple inspection standard in the industry, and the manufacturer will also test the change trend of the buzzer, frequency response curve and other parameters, but these test equipment are generally not qualified for users to achieve, but generally use electromagnetic passive buzzer users do not require these two parameters, usually do not affect the use, unless some users require the use of multi-frequency points, then the frequency response curve must be tested; If you encounter special occasions, or need more advice, please send us feedback.