11mm Piezo Ceramic Buzzer Element

Core Characteristics

A resonant frequency of 7.8 kHz sits in a range that is both easily perceived and less likely to be masked by low‑frequency environmental noise, which is useful for indoor consumer and medical products.

At only 0.18 mm thick, the ceramic and substrate stack can be bonded directly to a PCB or a thin metal diaphragm, allowing the entire sound‑generating assembly to stay below 1 mm in height.

The 12000 pF capacitance, measured at 120 Hz, presents a high capacitive load that reduces the voltage swing needed to achieve a given sound pressure level, making direct 3.3 V PWM drive viable.

A brass substrate provides good thermal conductivity, helping to stabilise the resonant frequency during continuous operation and offering a reliable surface for soldering or conductive epoxy attachment.

An equivalent resistance of ≤500 Ω limits mechanical damping, which allows LC resonant boost circuits to reach higher Q factors and generate greater acoustic output from a low supply voltage.

The operating temperature range from -20 °C to +70 °C covers the environments typical of consumer electronics, medical devices and industrial sensors.

Typical Applications

Smart wearable devices, including fitness trackers and smartwatches, where the 0.18 mm profile helps maintain a slim overall product thickness while providing clear notification tones.

Portable medical diagnostic tools such as glucose meters, pulse oximeters and digital thermometers, which benefit from a simple, low‑voltage audible indicator that does not add bulk.

IoT sensor nodes, from door/window sensors to water leak detectors, where the element can be driven directly by a 3.3 V MCU and the tone is distinct enough to be noticed in a home environment.

Industrial proximity sensors and small automation panels that need a compact acoustic feedback element compatible with standard SMD and through‑hole assembly processes.

Consumer appliance control boards in products such as microwave ovens, washing machines and induction cooktops, where the bare element can be integrated cost‑effectively into the existing PCB.

Toy and novelty electronics that require a simple, inexpensive sounder for interactive feedback, musical tones or alert sounds.

Frequently Asked Questions

1. What mounting method is recommended for the FT‑11T‑7.8A1?

Conductive silver epoxy is the most common choice for permanent PCB attachment because it avoids the thermal stress that soldering can place on the thin ceramic layer. If a solder connection is preferred, the heat should be applied to the brass substrate edge only, keeping the tip temperature below 280 °C for no more than three seconds. Spring‑contact retention is also used when the element needs to be field‑replaceable.

2. How does the 7.8 kHz tone compare with lower‑frequency buzzers?

At 7.8 kHz, the wavelength is short enough to work efficiently from very small cavities, yet the frequency is still well below the ultrasonic range where directivity becomes extreme and perception drops off. In practice, the tone is clearly audible in a typical room and is not easily confused with mechanical hum from fans or motors.

3. Can the FT‑11T‑7.8A1 be run continuously?

Yes, continuous operation is possible across the full -20 °C to +70 °C range. When driven directly from a 3.3 V GPIO without an LC boost, self‑heating is negligible. At higher drive voltages obtained through resonant boosting, the brass substrate dissipates heat efficiently enough to prevent frequency drift in open or ventilated enclosures. For sealed designs, a reduced duty cycle or lower drive voltage may be advisable; MEIDI can provide lifetime data for specific operating conditions.

4. Are custom electrode patterns or substrate materials available?

Yes. While the standard configuration uses a full‑face silver electrode on a brass disc, MEIDI can supply segmented electrode patterns, alternative diameters, nickel or gold electrode finishes for improved corrosion resistance, and substrates made from stainless steel or phosphor bronze. Custom orders are subject to engineering review, minimum quantities and extended lead times.

5. How does the capacitance tolerance affect the LC resonant boost circuit?

The nominal 12000 pF capacitance is specified at 120 Hz; at 7.8 kHz the effective capacitance drops slightly. For a practical LC boost design, an inductor around 4.7 mH to 10 mH is typically used together with a small parallel capacitor to accommodate the ±30 % tolerance. MEIDI provides the actual measured capacitance of each sample unit, allowing designers to select a precise inductor value for their prototype.