Jaycar 4kHz Electro-Acoustic Audio Transducer – Speaker or Knock Sensor in One Part

You're building a project and you need something that turns voltage into sound — or sound into voltage. No PCB, no amplifier board, no fuss.

This Jaycar 4kHz transducer is the raw component. Feed it an AC signal and it pushes out sound pressure waves at its resonant frequency. Flip the wiring and it becomes a knock or vibration sensor, generating an AC voltage when something hits it. One part, two jobs.

It ships in a black plastic casing that bolts or screws into your enclosure. Need a different form factor? It's deconstructible. Resonant frequency is 4kHz ± 0.5kHz, electrostatic capacitance 25,000pF ± 30%. Add to cart and get it on your bench this week

• Dual-function: works as a speaker driver or a knock/vibration sensor
• Resonant frequency: 4kHz ± 0.5kHz
• Electrostatic capacitance: 25,000pF ± 30%
• No internal electronics — pure electro-acoustic component for flexible project use
• Supplied in a black plastic casing for easy mounting; deconstructible for alternate applications