A surgical instrument comprising a tissue-compressing device comprising opposing compression surfaces, a switching element having first and second switching states changed solely by mechanical movements, a biasing element mechanically coupled to the switching element, the biasing element retaining the switching element in one of the first and second switching states until a pre-determined force is imparted to the switching element, wherein the pre-determined force is an amount of force proportional to an optimal tissue compression force of compressed tissue disposed between the opposing compression surfaces and the switching element is positioned in line with the tissue-compressing device to cause a force, proportional to a force placed upon compressed tissue disposed between the opposing compression surfaces, to be imparted to the switching element.