English
The 4216 Active Piezo Alarm Buzzer is a self‑driven piezoelectric alarm that combines a 41.8 mm diaphragm with a built‑in oscillator, producing a fixed 2800 Hz tone as soon as DC power is applied. Measured sound pressure at 10 cm reaches 101–107 dB, well above the 90 dB guaranteed minimum. The alarm operates across a 3–24 V DC range, drawing less than 8 mA at 12 V, and its threaded housing can be securely mounted on control panels or machinery subject to vibration.
Acoustic output verified at 101–107 dB on a 10‑unit sample batch, providing substantial headroom for noisy industrial floors and enclosed panels.
The 3–24 V supply range eliminates the need for external converters, covering 12 V vehicle systems, 24 V fire alarm loops and deeply discharged battery supplies.
A large 41.8 mm piezoelectric ceramic delivers a clean tonal character with minimal harmonics, distinguishing it from coil‑driven electromagnetic sirens.
The integrated oscillator generates the alert tone immediately upon applying voltage, removing the need for microcontroller PWM resources or external driver transistors.
Threaded bezel mounting provides stronger mechanical retention than pin‑through designs, an important consideration for equipment exposed to constant vibration or outdoor conditions.
Current draw stays below 8 mA at the nominal 12 V, which places very little load on backup battery circuits during extended outages.
| Parameter | Value | Test Conditions |
| Product Type | Electronic Alarm / Siren | — |
| Rated Voltage | 12 VDC | Nominal |
| Operating Voltage | 3 – 24 VDC | Continuous |
| Sound Output at 10 cm | ≥ 90 dB | At 12VDC, 2800 Hz, free field |
| Sample SPL Range | 101 – 107 dB | 10‑unit batch, 12Vp‑p, 10 cm |
| Resonant Frequency | 2800 ± 500 Hz | Built‑in oscillator |
| Sample Frequency Range | 2860 – 2950 Hz | Batch clustering |
| Operating Current | ≤ 8 mA | At 12VDC |
| Capacitance | 12 ± 40% nF | At 1 kHz, 25 ℃ |
| Operating Temperature | -20 ℃ ~ +80 ℃ | Continuous |
| Storage Temperature | -30 ℃ ~ +85 ℃ | Non‑operating |
| Dimensions (Dia × H) | 41.8 × 16 mm | Body excluding threaded section |
| Weight | 12 g | Typical |
| Housing Material | Black ABS | — |
| Mounting Type | Through‑hole with threaded bezel | Panel‑mount capable |
| Soldering (Wave) | 260 ± 5 ℃, 4–6 s | 2–3 passes max |
| Soldering (Manual) | 350 ± 10 ℃, 2–5 s | 2–3 passes max |
Sound Pressure: 101 – 107 dB (mean 103.2 dB)
Frequency: 2860 – 2950 Hz (all within ±500 Hz tolerance)
Diameter: 41.79 – 42.00 mm
Height: 15.99 – 16.05 mm
Industrial machinery alarm systems where the 101+ dB output cuts through 85–90 dB factory noise, ensuring fault and emergency stop alerts are noticed immediately.
Heavy equipment proximity warnings on cranes, forklifts and presses, where the threaded mount resists loosening caused by continuous vibration.
Security and perimeter detection panels that benefit from the 2800 Hz tone’s ability to carry over 50 metres in open yards.
Vehicle and marine hazard signalling, powered directly from 12 V or 24 V buses without additional regulation.
UPS and backup battery systems that require a low‑power alarm for thermal runaway or overload conditions, drawing only 8 mA to preserve stored energy.
Solar and off‑grid power installations where the 3 V minimum operating voltage keeps the alarm functional even during deep battery discharge.
| Safety System Requirement | HND‑4216 Advantage |
| Long‑range hazard audibility | Measured 101–107 dB ensures alert audibility 40–60 metres away in 85 dB ambient noise. |
| Eliminate external drive complexity | Built‑in oscillator; only a DC voltage is needed to start the tone, saving I/O and driver components. |
| Survive variable power quality | 3–24 V range handles automotive cold‑crank, 12 V nominal and 24 V industrial rails without converters. |
| Resist vibration and mechanical stress | Threaded bezel panel‑mount provides stronger retention than pin‑through designs; ABS housing tolerates 350 °C manual rework. |
| Minimize power burden on backup systems | ≤8 mA at 12 V draws about 75 % less current than comparable electromagnetic sirens, extending battery runtime. |
MEIDI Intelligent Technology has manufactured acoustic warning devices since 2011. The factory in Jiangsu, China, integrates in‑house ABS moulding, automated oscillator calibration and 100 % acoustic verification under an ISO 9001‑certified quality system. This vertical integration allows close control over the HND‑4216’s performance and reliability.
Each production batch undergoes the following checks. Sound pressure is measured on every unit to confirm the ≥90 dB minimum; typical batch averages exceed 103 dB. Oscillator frequency is verified to remain within 2800 ± 500 Hz, and current consumption is screened to ≤8 mA at 12 V. Thermal endurance testing runs units for 48 hours at +80 °C to confirm oscillator stability. Humidity exposure at 40 °C and 93 % RH for 96 hours validates the ABS housing and terminal plating. Solderability is tested per J‑STD‑002, and vibration testing across 10–55 Hz with 1.0 mm amplitude ensures the threaded mount remains secure.
A lot code printed on the housing links every HND‑4216 to its production date, oscillator batch and full test records, retained for ten years.
1. Can the 4216 Active Piezo Alarm Buzzer be used outdoors in rain or high humidity?
The standard ABS housing is designed for indoor and sheltered outdoor use. For direct exposure to rain, washdown or heavy dust, contact MEIDI about an IP‑rated version with a sealed bezel and drainage path. Mounting the alarm with the sound port facing downward can also help protect the internals.
2. What is the effective alerting distance in a noisy factory?
With a measured output of 101–107 dB, the HND‑4216 typically provides a clear signal up to 40–60 metres away when background noise is around 85 dB. In very loud areas (95 dB and above), the range may reduce to 25–35 metres. For large spaces, multiple alarms spaced 30–40 metres apart are recommended.
3. Can the tone be customised, or is it fixed at the factory?
The standard unit produces a steady 2800 Hz tone. For volume OEM projects, MEIDI can evaluate alternative frequencies within the piezoelectric resonance band or add modulation patterns. Minimum order quantities and engineering lead times apply.
4. Is the HND‑4216 safe to run continuously for 24 hours?
Yes. The alarm is rated for continuous duty, and its low 8 mA current generates very little internal heat. Both the piezoelectric element and the oscillator circuit remain well within their thermal limits during extended operation across the full -20 °C to +80 °C ambient range.
5. Can the alarm work with 48 V DC or 110 V AC supplies?
The maximum continuous voltage is 24 V DC. For 48 V systems, a simple zener clamp or series resistor can reduce the voltage to a safe level. For 110 V AC, a bridge rectifier with 24 V regulation is needed. Application notes for these setups are available from MEIDI. Custom high‑voltage variants are not produced for this model.
For acoustic coverage calculations, IP sealing options, OEM customisation requests or volume pricing, send your requirements through the enquiry form. The applications engineering team at MEIDI normally responds within one business day with data sheets, mounting drawings and sample availability.
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No.6, Wenlin Road, Chenbao Town, Xinghua City, Jiangsu Province, China
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