How does a tuning fork switch work?

The Working Principle of a Tuning Fork Switch: Vibration Sensing, Precise Judgment

The core working principle of the tuning fork switch is based on the principle of level detection through "resonant frequency change." By the collaborative action of the built-in electronic circuit and mechanical structure, it achieves precise judgment of the existence status of materials.

The mechanical structure consists of a pair of metal tuning forks, an excitation coil, and a detection coil, with the electronic circuit responsible for providing excitation signals and processing feedback signals. Upon applying power, the excitation coil generates an alternating magnetic field under the drive of the electronic circuit, causing the tuning forks to vibrate at their natural resonant frequency (typically 100~1000Hz). At this point, the detection coil senses the vibration state of the tuning forks in real-time and feeds back to the control circuit.

When the material (liquid or solid) contacts the tuning fork, its damping effect causes the vibration frequency of the tuning fork to plummet, sometimes even stopping the vibration. The detection coil captures this frequency change and transmits the signal to the electronic processing unit. The processing unit quickly analyzes and determines that the material has reached the preset position, and then outputs a switching signal (selectable between normally open or normally closed), triggering subsequent control actions such as alarms, pump start/stop, or valve operation.

When the material level or position drops and detaches from the fork surface, the damping resistance on the fork disappears. Under the action of the excitation coil, the fork returns to its inherent resonant frequency, and the electronic circuit outputs a reverse switching signal, completing a detection cycle. The entire process does not require contact measurement and is not affected by the physical properties of the material. With its simple and reliable principle, it achieves rapid and accurate judgment of the level status.