I have tested them multiple ways, here's how:
I have two humidors. I put a humidifying device in the humidor, and 2 analog hygros. I also put in 3 of the digitals. I left those there overnight. The result was that the analogs read 70% (which is what it should read) and the digitals all read different readings. One was 42, one was 45 and the other was high 30s.
Test two: Place digital hygro in snake tank next to analog hygro. Analog read 53%, digital read 37%.
Test three: Took all 4 digital hygros, and placed them in a small tuperware dish. Then got a small cap of salt, and moistened it with water. Sealed it up very tight and let it sit overnight. After 8 hours, it should have read 75% (or close) on all of them. They were each at 40 something percent each.
Test four: place a wet rag around your hygro and leave it for an hour. It should read 96% or so after 1 hour. The reading after 1 hour was 55%.
All these tests EXCEPT 4 were done on the hygro itself and not the probe that is attached via cord.
I have already purchased 2 additional hygros for my humidor, because those poor smokes cant get destroyed!
http://www.cigarmony.com/index.asp?P...PROD&ProdID=82
But I dont know what to do about the current 4 I have.