Electromagnetic acoustic transducer S7694 DATA SHEET MAIN TECHNICAL SPECIFICATION straight-beam electromagnetic acoustic transducer with permanent magnet for generating and receiving shear waves with linear polarization 3 MHz  10% 18x12 mm 1 to 200 mm (when using A1270 EMAT) up to 4 mm (for inspection range up to 50 mm) 600 V 7 ± 2 Ohm -30 to +60 ◦ C 40x56 mm LEMO ERN.00.250 215 g Transducer type: Nominal frequency: Effective aperture diameter: Inspection range: Lift-off/through-coating thickness: Maximal excitation pulse voltage: Direct current resistance of signal inductor: Operating temperature rang: Overall dimensions: Type of socket: Weight: MEASUREMENT CONDITIONS AND EQUIPMENT Reference excitation signal: unipolar square pulse with amplitude 400 V ± 40 V, pulse duration 200 ± 13 ns by 50% of the maximum voltage amplitude. Reference block: CO-2, steel 20, serial number 006 longitudinal wave velocity 5930 m/s, shear waves velocity 3247 m/s. Measured pulse: echo pulse from the backwall of reference block, depth 30 mm. Induced noise: white thermal noise with 2 mV effective amplitude, generated in inductor coil placed adjacent to the protector of the transducer. MEASURED CHARACTERISTICS Amplitude frequency response Shape of the measured echo pulse Echo pulse duration: Echo pulse amplitude Ae : Bandwidth Π: Relative bandwidth Bw : © Acoustic Control Systems Peak frequency fp : Lower cut-off frequency fl : Upper cut-off frequency fu : Centre frequency fc :

Reverberation noise curve (RNC) Time, µs Signal-to-noise ratio between the backwall signal in the reference block and transducer self-noise: Signal-to-noise ratio between the backwall signal in the reference block and transducer self-noise in presence of electromagnetic noise: RNC level at 5 µs: Time, µs Amplitude of the first maximum of ACF: Time position of the first maximum of ACF: Note: The RNC is normalized by test excitation signal amplitude and given in logarithmic scale. Transducer RNC is indicated by the solid line. The dash line shows the amplitude of induced noise in sum with the RNC....