?? _ ?좉컼吏???_ 湲곗?吏???/font> _ Buzzer Technology 
 
 
   Sound Pressure Level(dB)
 
   Harmonics
- A wave whose frequency is a whole-number multiple of that of another.
- There is no sound that include only fundamental tone.
- Ratio of harmonics can be benchmark of distortion.
?? Theory : Fourier Transform        Experimental Method : FFT Analyzer
 
   F0
- Resonant Frequency of Buzzer Max. SPL / Min. Current / Max. Magnitude.
- Can be controled by Shape, Voltage, and so on.
 
   Frequency Response
- General indication way of buzzer specification.
 
   Rated Voltage
- The level of input voltage that is required for the Buzzer to operate as designed.
- Defined as a rectangular voltage of duty 50%, 0-p.
 
   Rated Voltage
- Generally Buzzer uses 500 ~ 5,000 Hz.
 
 
No.
Part Name
Material
Function
1.
Upper Case
LCP
 - Guard Vibration Parts
 - Guide Sound Way
2.
Magnet Plate
Permalloy
 - Control F0 / SPL
3.
Resonator
Permalloy
 - Control F0 / SPL
4.
Magnet
Sm-Co
 - Supply Magnetic Energy
 - Permanent Source
5.
Coil

3DS-FC

 - Input Electrical Power
 - Generate Driving Force
6.
Yoke
Fe,Pure Iron
 - Make Magnet Circuit
7.
Lower Case

LCP

 - Guard Vibration Parts
 - Hold Assembly
8.
Terminal
PBS
 - Connect Outer Parts
   Operating Principle
- The resonator fixed at parallel point between the attractive force by yoke caused by magnet flux and the stiffness of itself.
- If the alternating current induced at coil, this signal superposed with magnet flux and attractive force varies with input square wave signal
- According to vibration of resonator, the sound created.
 
   Vibration Shape of Resonator
 
 
   Design of Air-gap
- Important factor of buzzer design
- Increase performance when gap is as close as possible.
- Problems when the buzzer has too small gap.
  1)The pulling force of magnet increase greater than the stiffness of resonator, the resonator sticks to the yoke.
  2) The magnetic field increase too stronge, AC magnetic flux cannot drive.
  3) The deviation of gap greatly concern with its performance.
 
   Characteristic Control
- Satisfy user???requirement : Adjust F0, SPL, Z
- If some bandwidth required, generally suggest 2.5~3kHz band because it is sensitive to human ear
- Melody or voice alarm require much wide band
 
   Minimizing Design
- Decrease resonator???area : Increase resonator???stiffness & F0 : Decrease efficiency
- Adopt rare-earth magnet(?? up) : Wider range SPL (melody, alarm)
- Adopt super-thin Permalloy(30??
 
   Resonance Effect of Helmholtz
  * Expansion of the band
 
  ?In order to widen the frequency band to be used to 2,048Hz~2,700Hz
  ?If the D(1.7mm) is slightly reduced to 1.5mm, fo becomes 2,460Hz
  * Raising the Sound Pressure
 
  ?In order to increase SPL of 2,048 Hz, external resonator set at 4,100Hz
  ?If the D=3.3mm assumed, fo becomes 4,270Hz
 
 
   Driving Circuit of Buzzer(HS Standard)    Driving Circuit of Buyers
 
   Maximize SPL Effect
- Realize higher SPL
- Design concept of sound guide box
 
  Volume Control Technique
? Base Current Control
?Collector Current Control
?Vcc Control
  - Control rated current in TR by
    using R
  - Control collect current in buzzer
    by using various R
  - Control magnitude of voltage
    of circuit
 
? Base Current Control
? Collector Current Control
  - Change ratio of square wave rating time
  - Fix driving circuit
  - Electrical control type
 
 
-
Please make reasonable space between sound emission hole of buzzer and housing wall of set.
It will be given different resonance effectivity and sound quality caused by helmhotltz.
-
Do not use any solvent material / or adhesive of solvent contents for installation into set housing.
-
Please use non woven screen / or some fabric screen to be not inserted any dust / foreign material / moisture into sound emission hole of buzzer.
-
Please match fitly to same direction between sound emission hole of buzzer and sound hole of housing.
 
-
Soldering processing should be applied based on NON SMD buzzer & SMD buzzer as follows ;
?/strong> NON SMD buzzer is to solder by hand soldering
?/strong> SMD buzzer is to solder through wave & reflow soldering that need to operate the temperature below than 240??
-
When the buzzer need to be washed with water, It should be used with washable buzzer that have sealed with label sticker at emission hole of buzzer.
-
To do art-work of PCB pattern, it needs to consider the buzzer location which it should be not closed to inductionable other component because it may be affected noise / or data error caused by radiation of magnetic flux from buzzer.