If There Is No Test Equipment, How To Verify The Performance Of Electromagnetic Passive Buzzer?

If the user does not have test equipment, he can test whether the electromagnetic passive buzzer is suitable for use in the following simple ways:
1. Take a piece of finished PCB that the user actually uses, or a PCB piece that has a complete circuit of the buzzer audio source output part.
2. Confirm whether the circuit parameters on the PCB are correct:
First, whether the power amplifier part of the circuit is correct, refer to Figure 1, in which diode IN4148 can be without;
Second, confirm whether the frequency of the signal generated on the PCB matches the selected buzzer (the signal frequency is preferably 50% duty cycle square wave, otherwise it will affect some parameters of the buzzer), the rated frequency of the selected buzzer must be the same as the actual use frequency or forward, pay attention not to choose the buzzer with a lower frequency; For example, your PCB output frequency is 2700Hz, you must choose a buzzer rated frequency of 2700Hz or 2600Hz, absolutely do not choose a buzzer with a rated frequency of 2700Hz or more, most of the buzzers use the frequency width is generally between 100-200Hz, so it is best not to choose a buzzer with a rated frequency of 2600Hz;
Third, confirm whether the power of the signal source on the PCB is sufficient to saturate the transistor of the power amplifier part of the buzzer, if it is not enough, the resistance value of R1 in Figure 1 must be reduced, and the resistance value of R2 must be less than the resistance value of the buzzer or 0 ohms;
Fourth, confirm whether the voltage of the buzzer amplifier part of the PCB matches the rated voltage of the selected buzzer, and the voltage is too small to make the parameters of the buzzer fail to meet the specifications of the specification;
Fifth, lead the wire from the part of the buzzer on the PCB to the test fixture, pay attention to the positive and negative poles do not connect wrong, the electromagnetic passive buzzer has clear positive and negative poles, can not be wrong;
Sixth, if there is no sound pressure meter, the minimum standard seal sample accepted by the volume can be compared and identified by listening; Because the human ear will have fatigue when listening for a long time, there will be a large deviation in listening in the fatigue state, so this method of testing will have a relatively large controversy, so if possible, it is best to use a sound pressure gauge (the commonly used sound pressure meter TES1351B on the market, at about 300 yuan, if the sample product reading is used for comparative testing, it is completely able to meet the requirements)