Stigma (letter) sigma form ς never occurs inside a word and is never used as a numeral either. Uppercase forms of stigma as a numeral (Ϛ) are rare in practice; when they occur, they can often be confused with uppercase forms of another numeral symbol, koppa (Ϟϟ), which stands for 90. Stigma is encoded in Unicode as "Greek letter stigma" U+03DA (Ϛ) and "Greek small letter stigma" U+03DB (ϛ). Stigma (letter) Stigma (ϛ) is a ligature of the Greek letters sigma (Σ) and tau (Τ), which was used in writing Greek between the Middle Ages and the 19th century. It is also
Electric torque wrench Electric torque wrench An electric torque wrench is a planetary torque multiplier or a "gearbox" mated to a brushless electric motor. At the end of the "gearbox" is a reaction device that is used to absorb the torque. This allows the operator of the tool to use the electric torque wrench with very little effort. These tools are primarily used anywhere accurate torque is required on a nut and bolt, or where a stubborn nut needs to be removed. These planetary torque multiplier gearboxes have multiplication ratios up to 4000:1. The correct torque output is adjusted by controlling the voltage.