GUSTAV KIRCHHOFF (1824- 87)

1845 – Germany

‘First law (Junction law): At any junction point in an electrical circuit, the sum of all currents entering the junction must equal the sum of all currents leaving the junction’

‘Second law (Loop law): For any closed loop in an electrical circuit, the sum of the voltages must add up to zero’

In equation form the first law is I = I1 + I2 + I3 + I4 +… where I is the total current and I1, I2, I3 etc. are the separate currents.

Second law is V = V1 + V2 + V3 + … where V is the total voltage and V1, V2, V3 etc. are the separate voltages.

These laws are an extension of OHM‘s law and are used for calculating current and voltage in a network of circuits. Kirchhoff formulated these laws when he was a student at the University of Konisburg.

Kirchhoff also showed that objects that are good emitters of heat are also good absorbers. This is Kirchhoff’s law of radiation.

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WILHELM GOTTLIEB DAIMLER (1834-1900)

1885 – Germany

‘Daimler was convinced that steam power was outdated’

early motor vehicle

In 1885 he perfected the first petroleum-injected internal combustion engine and produced the first motorcycle and the first four-wheeled petrol driven car.

The foundation for Daimler’s work had already been laid in the creation of two- and four-stroke gas-fuelled internal combustion engines by early pioneers Joseph Etienne Lenoir (1822-1900), Alphonse Beau de Rochas (1815-93) and Nikolaus August Otto (1832-91).

diamler-benz engine serial number

Although liquid petroleum was well-known, it had been of no use in developing the internal combustion engine because the liquid could not be compressed in the same manner as gas. The four-stroke engine awaited the development of the carburetor, which converted the liquid petroleum into a thin spray, which could be compressed and sparked.

In 1885 Karl Benz (1844-1929) designed and constructed a three-wheel vehicle powered by a 0.75 horsepower engine.

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