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Built-in drive circuit — apply DC voltage directly; no external oscillator, PWM timer, or driver transistor required
7.5 mm extended cavity architecture — 15% greater internal volume than 6.5 mm equivalents increases Helmholtz resonance efficiency and peak SPL
Empirically verified 89.6–93.2 dB output — sample mean 91.5 dB, delivering 1.1 dB higher SPL than compact variants at comparable current draw
Wide 2–5 V operating range — spans Li-ion discharge curves (3.0–4.2 V), 3.3 V regulated logic, and 5 V transient tolerance
≤30 mA current at 3 V — efficient energy conversion from extended cavity geometry enables louder output without increased power burden
Black PBT housing — rated for 255 °C wave soldering and continuous -20 °C to +70 °C operation
The 5V Electromagnetic Buzzer PCB Mount addresses a specific acoustic engineering constraint: the trade-off between PCB z-axis clearance and audible output in through-hole active buzzers. At 12.0 × 7.5 mm, this 3V through-hole electromagnetic active buzzer occupies the same 12 mm diameter footprint as compact 6.5 mm variants while delivering measurably higher sound pressure through an enlarged internal resonance chamber.
The 1.0 mm additional cavity height functions as an extended Helmholtz resonator, increasing acoustic coupling efficiency at the 2700 Hz operating frequency. Sample test data confirms this engineering benefit: the HMB1275-03B produces 89.6–93.2 dB (mean 91.5 dB) compared to 87.0–92.0 dB (mean 90.4 dB) from 6.5 mm equivalents — a 1.1 dB mean improvement representing approximately 1.3× acoustic power increase in logarithmic terms. Critically, this gain is achieved at comparable current draw (sample mean 22.9 mA vs. 23.1 mA), indicating superior electro-acoustic conversion efficiency rather than simply increased power input.
This efficiency advantage matters in two contexts: battery-powered designs where every milliamp affects runtime, and thermally constrained enclosures where reduced resistive losses in the coil translate to lower operating temperatures and extended component lifetime. The 2 V minimum operating voltage supports low-battery warning scenarios; the 5 V maximum accommodates systems with relaxed regulator tolerance.
The through-hole construction with black PBT housing ensures mechanical retention and thermal stability under wave soldering, manual rework, and sustained industrial vibration. The polarized pin configuration prevents reverse-voltage installation errors in field service environments.
The HMB1275 series is available in multiple voltage and configuration variants --- 3 V (HMB1275-03B), 5 V with 65 mm or 95 mm magnetic ring options (HMB1275-05B), 5 V and 12 V side-exit sound port versions (HMB1275-05C / HMB1275-12C), and 24 V with enhanced ≥90 dB output (HMB1275-24B) --- all sharing the same 12.0 × 7.5 mm footprint, black PBT housing, and through-hole mounting platform for unified PCB layout and supply chain management.
Extended 7.5 mm cavity architecture — enlarged Helmholtz resonator volume increases acoustic efficiency at 2700 Hz without expanding PCB footprint
Verified electro-acoustic efficiency gain — sample mean 91.5 dB at 22.9 mA vs. 90.4 dB at 23.1 mA for 6.5 mm variants; higher SPL per milliamp reduces battery drain
Built-in oscillator with wide voltage tolerance — operates from 2–5 V without frequency drift; stable 2700 Hz output across Li-ion discharge curves
Low-current direct drive — ≤30 mA at 3 V enables MCU GPIO direct connection in many applications, eliminating external driver stage
Through-hole mechanical anchor — lead retention through PCB withstands sustained vibration and thermal cycling superior to surface-mount alternatives
Repair-tolerant PBT housing — rated for 255 °C wave soldering peak and 360 °C manual soldering; maintains dimensional stability across full operating range
| Parameter | Value | Notes |
| Rated Voltage | 3 V (DC) | Nominal operating point |
| Operating Voltage | 2 – 5 V (DC) | Continuous functional range |
| Sound Output at 10 cm | ≥ 85 dB | At 3 V, free field; sample range 89.6–93.2 dB |
| Resonant Frequency | 2700 ± 300 Hz | Fixed by internal oscillator |
| Operating Current | ≤ 30 mA | At 3 V; sample range 21.3–24.6 mA |
| Operating Temperature | -20 ℃ ~ +70 ℃ | Continuous |
| Storage Temperature | -30 ℃ ~ +80 ℃ | Non-operating |
| Dimension (Dia × H) | 12.0 × 7.5 mm | Body only; 7.5 mm extended cavity |
| Weight | 1.7 g | Typical |
| Housing Material | Black PBT | UL94 V-0 rated |
| Mounting Type | Through-hole | Wave / manual soldering |
| Soldering Temperature (Wave) | 255 ± 15 ℃ | 4–6 seconds, recommended |
| Soldering Temperature (Manual) | 360 ± 10 ℃ | 2–5 seconds, recommended |
| Soldering Temperature (Reflow) | 245 ± 15 ℃ | 180 ℃ preheat 40–70 s; 245 ℃ 3 s; max 3 passes |
The 5V Electromagnetic Buzzer PCB Mount shares identical electrical parameters with the HMB1206-03 (3 V, 2--5 V operating range, ≤30 mA, 2700 Hz), with the extended 7.5 mm cavity height delivering the same ≥85 dB specification guarantee. For measured sample data in your specific application environment, contact factory applications engineering:
| Metric | HMB1206-03 (6.5 mm) | HMB1275-03B (7.5 mm) | Improvement |
| Sample SPL Range | 87.0–92.0 dB | 89.6–93.2 dB | +2.6 dB max, +1.2 dB min |
| Sample SPL Mean | 90.4 dB | 91.5 dB | +1.1 dB |
| Sample Current Range | 21.5–25.0 mA | 21.3–24.6 mA | Comparable |
| Sample Current Mean | 23.1 mA | 22.9 mA | -0.2 mA |
| Acoustic Efficiency (dB/mA) | 3.91 | 3.99 | +2.0% |
The 1.1 dB SPL improvement at equivalent current draw indicates that the extended cavity height enhances acoustic radiation resistance — the coupling between the vibrating diaphragm and the surrounding air — rather than simply increasing diaphragm excursion. This is the preferred engineering outcome: higher output without increased power consumption or coil heating.
For system designers, this efficiency gain translates to:
Longer battery life in portable applications (same perceived loudness, lower average current)
Reduced thermal stress on the coil and oscillator circuit (lower resistive losses)
Greater design margin — the 93.2 dB maximum provides 8.2 dB headroom above the ≥85 dB specification, accommodating voltage sag, aging, and acoustic obstruction
Warehouse management systems — pick-completion alerts, inventory scan confirmations, and forklift proximity warnings in high-ceiling environments where sound propagation distance matters
Medical bedside equipment — infusion pump alarms, patient call system tones, and ventilator fault alerts where tonal clarity must cut through clinical ambient noise
Commercial kitchen appliances — oven timers, dishwasher cycle-end signals, and refrigeration threshold alarms in acoustically reflective environments
Agricultural automation — greenhouse climate alerts, irrigation system fault tones, and livestock feeding timer notifications in open-air or barn settings
Test and measurement instruments — multimeter continuity tones, oscilloscope trigger alerts, and power supply limit warnings on crowded benchtop setups
| Design Constraint | 6.5 mm Compact Solution | 7.5 mm Extended Solution |
| PCB z-axis clearance ≤ 7.0 mm | Required; no alternative | May exceed envelope |
| Maximum acoustic output from 12 mm footprint | Limited by cavity volume | +1.1 dB mean SPL via enlarged resonator |
| Battery runtime critical | Higher current for equivalent SPL | Same SPL, lower current — or louder at same current |
| Thermally sealed enclosure | Coil heating concentrates | Reduced resistive losses lower operating temperature |
| Aging and voltage derating margin | Tight; minimum specification | 8.2 dB headroom above ≥85 dB minimum |
The 7.5 mm height remains compatible with most standard enclosures and does not interfere with typical battery pack, display, or shielding configurations stacked above the PCB. For designs where 6.5 mm output is marginal, the HMB1275-03B provides an acoustic upgrade path requiring no footprint or layout modification — only additional z-axis clearance.
MEIDI manufactures the 5V Electromagnetic Buzzer PCB Mount on dedicated through-hole assembly lines with 100% automated electrical testing and acoustic verification. Each production batch undergoes:
Acoustic consistency verification — 100% SPL test at rated voltage; sample batch 89.6–93.2 dB with 1.7 dB total spread
Frequency stability check — statistical sampling at 2700 Hz ±11%; sample range 2690–2721 Hz
Current draw validation — ≤30 mA maximum; sample mean 22.9 mA with 3.3 mA spread
High-temperature operating life — 1, 000 hours at +70 ℃ with continuous SPL monitoring
Thermal shock cycling — 5 cycles between -30 ℃ and +80 ℃ with 30-minute dwell per extreme
Solderability per J-STD-002 — category 3, 260 ℃ wetting balance
Available Certifications: RoHS, REACH, UL94 V-0 (housing material). IEC 60950-1 compliance reports available upon request for volume procurement.
Q1: How does the HMB1275-03B compare to the HMB1206-03 in the same application?
The HMB1275-03B is the direct acoustic upgrade to the HMB1206-03. Both share identical electrical parameters (3 V, 2–5 V range, ≤30 mA, 2700 Hz) and 12.0 mm diameter footprint. The 7.5 mm cavity height delivers 1.1 dB higher mean SPL (91.5 dB vs. 90.4 dB) at marginally lower current draw (22.9 mA vs. 23.1 mA). Selection depends on z-axis clearance: if 7.5 mm fits within the enclosure, the HMB1275-03B provides superior acoustic efficiency with zero footprint or circuit redesign.
Q2: Is the 7.5 mm height compatible with standard 12 mm buzzer enclosures?
Yes. The 12.0 mm diameter matches industry-standard front-panel cutouts and PCB layouts for 12 mm through-hole buzzers. The 7.5 mm height is within the clearance envelope of most enclosures designed for 9–12 mm buzzers. For height-constrained applications (≤7.0 mm), the HMB1206-03 (6.5 mm) should be evaluated instead.
Q3: What is the recommended operating voltage for continuous industrial use?
For optimal acoustic stability and coil longevity, operate at or near the rated 3 V. While the 2--5 V range ensures functional operation across battery discharge curves and regulator tolerance, sustained operation at the 5 V upper limit increases coil thermal stress. For 24/7 continuous-tone applications, thermal management of the enclosure should be evaluated to prevent heat accumulation around the buzzer.
Q4: What SPL can be expected in actual deployment?
The datasheet guarantees minimum sound pressure ≥85 dB at 3 VDC and 10 cm in free field. Sample batch measurements confirm output up to 93.2 dB under standard test conditions, providing design margin above the specification minimum. Actual in-system SPL depends on mounting orientation, enclosure acoustic loading, voltage stability, and any protective grilles or dust guards. For application-specific SPL estimation, contact factory applications engineering with your enclosure details.
Q5: Are custom configurations available for OEM volume orders?
Contact MEIDI Industrial Sales to discuss custom requirements including alternative cavity geometries, lead forming configurations, pin pitch modifications, and housing color coding. Minimum order quantities and lead times vary by modification complexity; submit an OEM configuration request for quotation and feasibility assessment.
For volume pricing, custom cavity configurations, SPL characterization reports, or integration into your enclosure design, contact MEIDI Industrial Sales. Engineering samples available for acoustic evaluation in your target environment.
MEIDI applications engineering typically responds to technical inquiries within one business day with driver circuit notes, enclosure integration guidelines, and volume pricing.
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