It can also be done with an electronic datalogging instrument, the data from which can be downloaded to a PC for graphing/analysis. A human hair hygrometer is generally more accurate than an electronic humidity sensor, but the electronic version is less expensive, more easily moved around, and lets you save the data to a file. Tim Reeves |-----Original Message----- |From: Brian Ellis [mailto:[log in to unmask]] |Sent: Wednesday, October 11, 2000 2:33 AM |Subject: Re: Thermohidrograph | | |A thermohygrograph, which is what I assume you are meaning, is an |instrument to record the temperature and relative humidity. It usually |consists of a drum, rotating over 24 hours, on which is clipped a paper |chart, with two pens drawing squiggly lines, one attached to a bimetal |spiral for the temperature and the other to a hair hygrometer movement |for the humidity. Very useful for putting into rooms where you are |stencilling solder paste, etc. to check that the environment is |correctly controlled. | |Brian | |> "" wrote: |> |> Technetter, |> |> May I know what does the term "thermohidrograph" mean? Is it a test |> measurement for PCB? |> |> Regards, |> |> Jacob Pao | --------------------------------------------------------------------------------- TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF TECHNET Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------