There is an important difference between torr (mm Hg ) and microns -- at least in my experience. The former can use a simple TC (thermal conductivity) gauge. The latter needs something like a vacuum tube ("ionization") gauge.I would guess it some unspecified units of height of a column of mercury. (But I think you will have also made the same guess and I also think you will have guessed the same as me that the unit of distance is mm,) I am surprised that his teachers have not drummed into him the importance of specifying units rather than just a number,
Les.
Please express in millibar or Pascal.Hi, I'm after a circuit design for a vacuum pump control, I need it to pull 4hg with pressure peaks of up to 10hg , unsure on how to design it, very new to this. All help is appreciated. Thanks in advance.
Vacuum units are a strange mashup of related units. Pascal is the offical SI unit but most of the US industrial (high-vacuum physics and engineering) high vacuum units display in mTorr (millimeter of Hg) or Torr.Please express in millibar or Pascal.
Picbuster
In my experience years ago, a Torr was a mm of Hg, and we commonly expressed the pressure as an exponent of Torr, e.g., 10^-6 Torr. Didn't use the "mashup" of mTorr.Vacuum units are a strange mashup of related units. Pascal is the offical SI unit but most of the US industrial (high-vacuum physics and engineering) high vacuum units display in mTorr (millimeter of Hg).
Even worse: many commercial/scientific instruments use mbar as the basic unit of vacuum measure.Vacuum units are a strange mashup of related units. Pascal is the offical SI unit but most of the US industrial (high-vacuum physics and engineering) high vacuum units display in mTorr (millimeter of Hg) or Torr.
https://www.mksinst.com/product/Category.aspx?CategoryID=525
Normal US SEMI practice is to use the mTorr (old school microns) mashup with rough vacuum as it gives nice scaled (0 to ~1000 max) numbers on a display gauge in the pumps operational range and then switch to exponent notation in high vacuum where the decade is the main scale of vacuum quality.In my experience years ago, a Torr was a mm of Hg, and we commonly expressed the pressure as an exponent of Torr, e.g., 10^-6 Torr. Didn't use the "mashup" of mTorr.