difference between american wire gauge and standard wire gauge
Standard wire gauge SWG was fixed by Order of Council August 23, 1883. It was constructed by improving the Birmingham Wire Gauge. It was made a legal standard on March 1, 1884 by the British Board of Trade. SWG is not to be confused with American Wire Gauge which has a similar but not quite interchangeable numbering scheme.
Strain gauge A typical strain gauge arranges a long, thin conductive strip in a zig-zag pattern of parallel lines. This does not increase the sensitivity, since the percentage change in resistance for a given strain for the entire zig-zag is the same as for any single trace. However, a single linear trace would have to be extremely thin and hence liable to overheating (which would both change its resistance and cause it to expand), or would have to be operated at a much lower voltage, making it harder to measure resistance changes accurately.