AE sensor with external (built-in to the sensor cable) preamplifier
- Acoustic-emission detectors (AE sensors) are mandatory for all AE diagnostic systems. Each AE channel contains an AE sensor and a preamplifier with the required wiring. Active sensors have built-in preamplifier, passive sensors need external preamp. Usually the sensors are fixed on the clean surface of the object to be inspected, and some appropriate, acoustically transparent contact material or glue is used.
- For the AE diagnostic systems, the most common type of sensors is the piezoelectric detector. It converts the received mechanical waves to electric signal with wide amplitude dynamics. The working frequency band of most popular resonance-type piezo sensors is somewhere between 30 kHz and 1 MHz. On the other hand, piezoelectric sensors have high output impedance. The main role of low-noise preamp is to gain up the output signal level and matching the output impedance to the connecting cable.
- Piezoelectric detector may operate in the opposite way, too: by the applied voltage impulse it will change the shape and hit the surface on which it was fixed. These artificially generated sound waves can be detected by other AE channels. The preamplifier must be able to pass these applied voltage impulses to the sensor for having this testing possibility.
- At this time, there are two resonance-type piezoelectric AE detectors offered to the SENSOPHONE AE diagnostic systems: the passive sensor S-15P and the active sensor with built-in preamplifier S-15PA. Both of them have built-in fixing magnet, too.
- It is possible and allowed to use in SENSOPHONE AE diagnostic systems any other type of passive sensors, if the external SENSOPHONE preamplifier can be connected to it. An active AE sensor can be used only in case when its built-in preamplifier is compatible with the SENSOPHONE systems.
Passive AE sensor S-15P
Active AE sensor S-15PA
AE sensor DAE