Hydrogen peroxide tank level measurement. The level gauge is a measuring instrument based on the principle of time travel. The radar wave runs at the speed of light. The operating time can be converted into a liquid level signal by electronic components. The probe sends out high-frequency pulses and propagates along the cable. When the pulses meet the liquid level surface, they are reflected back and received by the receiver in the meter, and the distance signal is converted into a liquid level signal.