Hello EEVryone,
I am using an acoustic emissions sensor to measure ultrasound (10 to 100 kHz). The sensor is a piezo-electric transducer, I attached the datasheet below. The sensor connects directly to my scope's input via BNC. My problem is that the signal can be too high for my scope to handle and there is no switch (10x / 1x) like you would find on a probe. I'm guessing the voltage would peak at 15 V and the power is very low. I think 10x (20dB?) would be perfect.
I was surprised to find nothing about choosing and using attenuators on Youtube or EEV blog. (except for high power RF measurement). I am looking at the Rigol RA5040K 40dB Attenuator. I assume this would mean the signal would be attenuated 100x, which is more than I would like. I often have millivolt and volt level signal in the same measurement, the millivolt signals might get lost in the noise.
I am also not sure what the effect of the 50 Ohm impedance would be. Because the signal has such low power I am concerned the 50 Ohms will essentially act as a short and kill the signal. I'm assuming the impedance of a normal probe is in the Mega ohms even when the 10x attenuation is selected.
One "solution" is to cut the BNC off a probe that has the attenuation switch in the BNC side and connect that to my sensor. So how do I attenuate the signal without chopping the BNC connector off my expensive Acoustic Emissions sensor? Is there a high impedance 20 dB (10x) BNC attenuator?
Thanks for helping,
Mike