What Are the Key Specifications of a 9x4.2mm SMD Electromagnetic Passive Buzzer
2026-10-16
When designing compact electronic products, engineers often need a miniature sound component that delivers reliable acoustic performance without occupying valuable board space. The 9x4.2mm SMD Electromagnetic Passive Buzzer from MEIDI is engineered to meet exactly this demand, combining a small footprint with stable electromagnetic driving characteristics. Understanding its key specifications helps designers integrate it correctly, avoid compatibility issues, and achieve consistent audio output across mass production.
MEIDI has focused on electromagnetic acoustic components for years, and the 9x4.2mm SMD Electromagnetic Passive Buzzer reflects that accumulated manufacturing experience. Below is a professional breakdown of the parameters that matter most.
Core Specifications at a Glance
| Parameter | Typical Value | Notes |
|---|---|---|
| Dimensions | 9 x 4.2 mm | Surface-mount package |
| Type | Electromagnetic, passive | Requires external drive signal |
| Rated Voltage | 3 V / 5 V options | Depends on model variant |
| Operating Voltage | 2–5 V | Wide compatibility |
| Rated Frequency | 2731 Hz ± 300 Hz | Common resonance point |
| Sound Pressure Level | ≥ 75 dB @ 10 cm | At rated voltage and frequency |
| Coil Resistance | 16 ± 3 Ω | Typical for 3 V version |
| Current Consumption | ≤ 80 mA | At rated conditions |
| Operating Temperature | -20°C to +70°C | Standard commercial range |
| Storage Temperature | -30°C to +80°C | Non-condensing |
| Termination | SMD pads | Reflow solder compatible |
| RoHS | Compliant | Environmentally friendly |
Why These Specifications Matter
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Passive design: The 9x4.2mm SMD Electromagnetic Passive Buzzer does not contain an internal oscillator. It relies on an external square wave, allowing full control over tone frequency and rhythm.
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Compact 9x4.2mm footprint: Ideal for wearables, medical monitors, handheld instruments, and IoT devices where board space is critical.
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Electromagnetic mechanism: Produces a warmer, fuller tone compared to piezo alternatives, with strong low-frequency response.
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SMD termination: Supports automated reflow soldering, reducing assembly cost and improving consistency.
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Stable SPL: MEIDI tunes each unit to maintain sound pressure within a narrow tolerance, ensuring uniform user perception.
Design and Integration Considerations
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Drive circuit: Use a transistor or dedicated driver IC capable of switching at the rated frequency.
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Resonant frequency: Driving near 2731 Hz yields maximum output;偏离 reduces SPL.
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Duty cycle: A 50% square wave is recommended for optimal acoustic efficiency.
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PCB layout: Keep traces short and avoid placing the buzzer near high-current switching nodes.
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Reflow profile: Follow standard lead-free soldering curves; avoid excessive thermal stress.
MEIDI Quality Assurance
Every 9x4.2mm SMD Electromagnetic Passive Buzzer from MEIDI undergoes 100% functional testing, including frequency response, SPL, impedance, and insulation checks. Batch traceability and RoHS documentation are available for qualified projects.
Frequently Asked Questions
Q: Can the 9x4.2mm SMD Electromagnetic Passive Buzzer operate directly from a microcontroller GPIO pin?
A: No. The 9x4.2mm SMD Electromagnetic Passive Buzzer typically draws 60–80 mA at rated voltage, which exceeds the safe current limit of most GPIO pins. A transistor, MOSFET, or dedicated buzzer driver should be used to switch the coil current, with a flyback diode placed across the buzzer to suppress voltage spikes.
Q: What is the difference between the 3 V and 5 V versions of the 9x4.2mm SMD Electromagnetic Passive Buzzer?
A: The main differences are coil resistance and rated current. The 3 V version usually has a lower coil resistance and draws more current, while the 5 V version has higher resistance and lower current. Both share the same 9x4.2mm footprint, but the drive circuit and supply rail must match the selected variant to achieve the specified sound pressure level.
Q: Is the 9x4.2mm SMD Electromagnetic Passive Buzzer suitable for reflow soldering and automated assembly?
A: Yes. The 9x4.2mm SMD Electromagnetic Passive Buzzer is designed with heat-resistant materials and SMD pads compatible with standard lead-free reflow profiles. It can be placed by pick-and-place equipment and soldered in a reflow oven, making it suitable for high-volume automated production.
Contact Us
For datasheets, samples, pricing, or custom specifications of the 9x4.2mm SMD Electromagnetic Passive Buzzer, contact MEIDI today. Our engineering team will help you select the right model and support your project from prototype to mass production.