If you measured it for most cells it's about between -60 and -90 millivolts.

如果你测量一下的话,大部分细胞都在-60到-90毫伏之间

耶鲁公开课 - 生物医学工程探索课程节选

For this particular cell here it looks like it's about -75 millivolts, so the inside of the cell is a little bit more negative than the outside.

这个细胞的膜电位是-75毫伏,所以细胞内侧跟外侧比起来电势要低一些

耶鲁公开课 - 生物医学工程探索课程节选