SFM-27 Intermittent Active Buzzer – DC 3–24V Electronic Alarm Sounder
The SFM-27 Intermittent Active Buzzer is a compact electronic alarm sounder designed to generate an intermittent audible warning when powered by a DC voltage source.
Operating within a 3V to 24V DC range, this active buzzer features a built-in sound-generating circuit, eliminating the need for an external oscillator or PWM signal.
Its durable plastic housing, two-wire connection, and mounting flanges make it suitable for industrial equipment, electronic alarm systems, automation projects, and DIY electronics.
Key Features
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Intermittent Alarm Sound: Produces a repeating audible warning signal.
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Active Buzzer Design: Built-in sound-generating circuitry for direct DC operation.
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Wide Operating Voltage: Supports 3–24V DC.
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Simple Two-Wire Connection: Easy integration into electronic circuits.
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Compact Construction: Suitable for installation inside electronic equipment and control panels.
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Plastic Housing: Lightweight enclosure for general-purpose applications.
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Mounting Flanges: Designed for convenient mechanical installation.
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Industrial Applications: Suitable for equipment status indicators and warning systems.
Technical Specifications
| Parameter |
Specification |
| Model |
SFM-27 |
| Product Type |
Active Electronic Buzzer |
| Sound Type |
Intermittent / Repeating Alarm |
| Operating Voltage |
DC 3–24V |
| Signal Generation |
Built-in Oscillator |
| Connection |
2-Wire |
| Housing Material |
Plastic |
| Housing Color |
Beige |
| Dimensions |
Approx. 50 × 30 × 15mm |
| Wire Length |
Approx. 10cm |
| Weight |
Approx. 7g |
| Mounting Type |
Flange / Screw Mount |
| External PWM Required |
No |
Wiring and Connection
The SFM-27 uses a simple two-wire DC connection.
| Wire Color |
Function |
Connection |
| Red |
Positive (+) |
DC 3–24V Positive |
| Black |
Negative (-) |
Power Supply Ground |
Basic Operation:
- Connect the red wire to the positive terminal of a suitable DC power supply.
- Connect the black wire to the negative terminal.
- Apply a voltage within the specified 3–24V DC range.
- The buzzer produces an intermittent audible alarm.
- Disconnect the power supply to stop the sound.
Arduino and ESP32 Compatibility
The buzzer can be controlled using an Arduino, ESP32, or other microcontroller through a suitable transistor or MOSFET switching circuit.
Important: Do not connect the buzzer directly to a GPIO pin unless its current consumption is confirmed to be within the controller's output limits.
Applications
- Industrial Warning Systems
- Electronic Alarm Circuits
- Equipment Status Indicators
- Automation Control Panels
- Security and Alert Systems
- Arduino and ESP32 Projects
- Robotics Warning Indicators
- DIY Electronic Projects
- Machine Operation Alerts
Important Notes
- The SFM-27 is an active buzzer and does not require an external tone-generation signal.
- It produces an intermittent sound pattern rather than a continuous tone.
- Use a DC power supply within the specified 3–24V range.
- Check polarity before connecting power.
- Do not connect directly to AC mains voltage.
- Current consumption and sound pressure level are not confirmed.
- For microcontroller control, use an appropriate switching circuit.
- The buzzer is intended for general-purpose audible indication and is not a certified safety alarm device.
Package Includes
