Stigma (letter) 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 used as a numeral symbol for the number 6. In this unrelated function, it is a continuation of the old letter digamma (originally Ϝ, cursive form ), which had served as a numeral since antiquity and was conflated with the σ-τ ligature in the minuscule handwriting of the Middle Ages. The στ ligature (, ) was one of many ligature forms that came into widespread use as
Torque tester is an electronic device used to convert torque into an electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the torque being sensed deforms a strain gauge. The strain gauge converts the deformation (strain) to electrical signals. A torque transducer usually consists of four strain gauges in a Wheatstone bridge configuration. Torque transducers of one or two strain gauges are also available. The electrical signal output is typically in the order of a few millivolts and usually requires amplification by an instrumentation amplifier before it can be used. The output of the transducer is