SLASEC8B February 2017 – January 2019 PGA460-Q1
The driver mode is dependant on the transducer type. Two types of transducers are available for open-air ultrasonic measurements. Closed-top transducers are transducers which hermetically seal the piezoelectric membrane from exposure to air or destructive particles. Closed-top transducer are favorable in applications that are subject to harsh environmental conditions, such as exposure to outdoor elements, extreme temperature changes, and debris. As a result of the additional protection offered by closed-top transducers, a transformer-driven method is typically required to maximize distance performance.
Open-top transducers are transducers with vents or slots that expose the piezoelectric membrane to the air. Open-top transducers are favorable for controlled indoor applications to minimize the risk of the transducer becoming damaged. Open-top transducers do not require as much driving voltage as closed-top transducers to achieve maximum distance performance; therefore, a transformer is not necessary. For low-voltage driven transducers, such as open-tops, a direct-drive (or bridge-drive) method can be used as an alternative to a transformer. The direct-driven method can work on certain closed-top transducers, but the maximum achievable distance will be reduced.