One of the items that was brought in by a friend to a recent Repair Café event in Campbell River was a non-functioning portable humidifier, a Honeywell model HUD-200. I didn’t have time to get to it during the Café afternoon, but was able to fix it afterward. These devices are based on an ultrasonic “nebulizer”, basically a piezoelectric element in a high frequency oscillator circuit generating ultrasound waves in water, and thereby causing droplets to form and flow out in an airstream from a fan. The symptom was that water was flowing through the device, but no moisture was being created.
the nebulous humidifier
You can never ever test enough.