Humidifier-Stopped working, no mist! how to test Piezo?

[Aakash]

My humidifier stopped working, there is no mist coming out of it. I can hear the fan is running.

Can anybody let me know how can I check if the piezo is working or if I should replace the piezo.

Any suggestions please help.

[Haenk]

Not sure if this works, but maybe use a laserpointer and the piezo element as a "mirror" and project the laser dot. If the projected dot gets broader, when the cleaner is switched on, the piezo is working.

[wraper]

Replacing transducer most likely won't help since the problem most likely is in electronics which are driving it. Unless it's electrically shorted or has visually observable damage, not likely there is anything wrong with it.

[Xenon]

Those piezo thingies are also used in medical humidifiers. They fail when they run dry because of overheating (they are driven hard).
Often the failure is visible on the piezo surface. It has a discoloration in the center or the surface peels off (tiny blisters).
Do you see anything similar?

[Aakash]

There is no discoloration that I see of, is there any way to drive it externally with a function generator and get to know if it's working fine?

[james_s]

You could connect it to an audio amplifier, piezo elements are very commonly used as inexpensive tweeters.

[Aakash]

I don't have any idea to build an audio amplifier, do you have any base circuit that I can build?

[james_s]

Build? If you take 10 seconds to search with google you will find numerous circuits, but surely you already have some kind of audio device around? Or just buy a small amplifier module, you can get them for a few dollars or less.

[Renate]

I say that if it looks good, connect it to your scope and tap it lightly. You should see plenty of volts.