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 ---------------------------------------------------------------------------------