Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 20

The voltaic pile helped the discovery of the magnetic effect of current; however, surprisingly the relation between the current flowing in resistance and voltage across it, known as the Ohm's law, remained undiscovered. The primary reason was the unstable voltage supplied by the voltaic pile. The discovery of thermoelectricity by Seebeck in 1822 provided a constant voltage source to supply continuous electric current. Using the thermo‐piles in the year 1826, Ohm obtained a simple but powerful relation among voltage, current, and resistance. It was the beginning of the Electric Circuit Theory. However, only in 1850 Kirchhoff published his two circuital laws and opened the path for the development of the Network Theory. Kirchhoff also showed that Ohm's electroscopic force (voltage) and classical potential of Lagrange, Laplace, and Poisson are identical. Interestingly, Ohm's law could be viewed as a symbol of the International Scientific unity relating to Italy (Volta), Germany (Ohm), and France (Ampere). Based on the magnetic effect of current, in the same year, Johann Christian Poggendorff invented the galvanometer to detect the current in a wire. Kelvin improved its sensitivity by designing the mirror galvanometer in 1858 [B.1, B.6, B.7].