Question
What is resonance of Ultrasonic Sensors?
Answer
When an electrical signal is applied in pulses at a frequency close to the resonance frequency of the oscillator, even after the electrical signal has stopped, the ultrasonic vibration remains.
This is called resonance.
For a Reflective Sensor, if this continues for a long time, detection becomes impossible.
Standard Sensors for Detecting Ferrous Metals under Standard Conditions