Core Summary
Buzzer selection often gets stuck on three sets of issues: electromagnetic or piezoelectric, whether to include an oscillator, and SMD or THT. These three sets correspond to different circuits, assembly, and sounding methods. Aligning the supply voltage, installation space, and sounding requirements before deciding on the series can reduce sample rework and later modifications. DIGISOUND offers both electromagnetic and piezoelectric types, as well as various packages including wired, SMD, and THT, facilitating design continuity with existing production lines.
1. Electromagnetic and piezoelectric types differ in their sounding principles
Electromagnetic type, driven by a coil to excite the diaphragm
The electromagnetic buzzer contains a coil and an iron plate. When powered on, the magnetic field drives the diaphragm to vibrate and produce sound. Its starting voltage can be set relatively low, allowing it to operate within a wide voltage range of 3–30 V. The sound volume is also relatively full, making it suitable for applications such as alarms and notifications where clear and audible sound is required.
Piezoelectric type relies on the inverse piezoelectric effect of piezoelectric wafers
Piezoelectric buzzers leverage the inverse piezoelectric effect of piezoelectric ceramics, featuring low power consumption and long lifespan, making them particularly friendly to battery-powered devices. When paired with a waterproof enclosure, they can also be used in outdoor or vehicular environments subject to water spray and dust.
II. Should I bring my own oscillator
With oscillator: It rings as soon as powered on
The model featuring an integrated oscillator can produce sound upon the application of a rated DC voltage, with a straightforward peripheral circuit. It is ideal for low-cost solutions where additional driver logic is not required on the MCU.
Without oscillator: Frequency controllable
Piezoelectric wafers or buzzers without oscillators require an external square wave signal for driving. The advantage is that the sounding frequency and tone can be determined by the controller, making it more flexible for multi-tone prompts and variable frequency alarms, and also facilitating differentiation from other prompt tones.
III. SMD and THT: A Look at Production Line Processes
SMD is suitable for compact automation
Surface-mount packaging is small in size and can undergo reflow soldering along with the motherboard, making it suitable for modules with limited space and mass SMT production lines.
THT exhibits superior vibration resistance
The mechanical bond of punch welding is stronger, making it more stable in continuously vibrating equipment (such as vehicles and construction machinery), and the repair process is straightforward.
IV. Outdoor and Vehicle-mounted Protection Considerations
For alarm devices in factory areas, vehicle cabins, and outdoor cabinets, it is preferable to choose waterproof piezoelectric buzzers with IP67 protection to avoid sound reduction or internal short circuits caused by water spray and dust. Alarms used for reversing should also consider the operating temperature range to ensure normal sounding in both winter and summer.
V. Procurement Checklist
Supply voltage and whether it is wide-voltage (determining whether it is electromagnetic or piezoelectric, with or without an oscillator)
Installation method: SMD, THT, or wire-bond soldering
Required sound pressure level and sound emission distance (allowance should be made for high noise levels in the factory area)
Working environment: Temperature range, presence of water spray and dust emission (IP rating)
Is frequency/tone controllability required (opt for a solution without an oscillator)
Batch consistency and delivery time
Parameter Table (Comparison of Two Types of Buzzers)
> The above provides a general guide for model selection. Specific parameters are subject to the original DIGISOUND documentation. QN TECHNOLOGY offers selection and verification services for electromagnetic, piezoelectric, and various packaged buzzers. Please send us your power supply and installation conditions for comparison.
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