The Weston cell, is a wet-chemical cell that produces a highly stable voltage suitable as a laboratory standard for calibration of voltmeters. Invented by Edward Weston in 1893, it was adopted as the International Standard for EMF between 1911 and 1990.[1] This is a type of standard cell, which is a battery that produces a precisely known voltage in laboratory conditions at 20 degrees centigrade.[2]Brass cylinder with 4 connections at top. Two marked 'A' and the other two marked 'B'. Black plastic nob in the centre top. Written at top Weston Normal Cell I-0183 INT VOLTS AT 20 degrees CWeston Normal Cell H Tinsley & Co, London S E No 50498 No 8910weston cell, wet-chemical cell, stable voltage, voltmeters, edward weston, scientific instrument