The first recorded experiments with static electricity were carried out by Greek philosopher Thales of Miletus (624 BC – 546 BC) who noted that rubbing animal fur on various substances such as amber would cause them to attract specks of dust and other light objects. Of course static electricity had been experienced much earlier than this, via lightning and shocks from electric fish, but until relatively recently, these electric charges were thought to be different types of electricity.
In fact it wasn’t until Benjamin Franklin’s 1752 experiments with lightning that it was confirmed that these charges differed only in magnitude. Mr. Franklin also went on to re-label “Vitreous” and “Resinous” static charges as “Positive” and “Negative” static charges respectively. He was also the first to discover the principle of charge conservation. In 1748 he constructed a multiple plate capacitor, that he called an “electrical battery” by placing eleven panes of glass sandwiched between lead plates, suspended with silk cords and connected by wires.
Earlier discoveries that aided Franklin’s famous kite experiments were those of Stephen Gray (1666-1736), who carried out experiments with conductors and insulators. From these early discoveries it was found that a static electric charge could be carried over distance by a conductor, and prevented from draining away by an insulator.
Things were moving in the right direction then - but research really took a push when in 1799 Italian physicist Alessandro Volta (1745-1827) published his experiments with his ground-breaking invention, the Voltaic Pile. This was the first electric battery that could continuously provide an electric current to a circuit.
This battery is credited as one of the first electrochemical cells. An individual cell in the pile consists of two electrodes: one made of zinc, the other of copper, with electrolyte drenched cardboard sandwiched between each layer. The electrolyte is either sulphuric acid mixed with water or a form of saltwater brine. The zinc, which is higher in the electrochemical series than both copper and hydrogen, reacts with the negatively charged sulphate. The positively charged hydrogen ions (protons) capture electrons from the copper, forming bubbles of hydrogen gas. This makes the zinc rod the negative electrode and the copper rod the positive electrode.
It was found that by stacking the zinc and copper electrodes alternately, each with an electrolyte layer between, larger charges could be supplied from the Voltaic Pile as more layers were added. From this Volta was able to define Potential Difference, more widely known as Voltage.
With these and other discoveries as a base (and not having to wait on a handy lightning storm), research into electricity was able to rapidly flourish. Over the next 40 years, André-Marie Ampère was able to define electric current, Georg Simon Ohm defined resistance, Michael Faraday and Joseph Henry did pioneering research in electromagnetic induction, from which transformers, dynamos and electric motors were invented.
Research accelerated throughout the 19th century, with many notable discoveries and developments, until electricity eventually became a commercial proposition. By the 1850’s battery powered telegraph systems were already an established technology, and a means of generating reliable electric power for these systems was being investigated. In the 1880’s electricity generated at power stations became a reality and the first power distribution systems were installed in European and US cities to supply lighting, either in DC (Direct Current) or AC (Alternating Current) forms. By the 1890’s power generation and distribution had largely settled on supplying AC power in three ‘phases’ and the modern electricity supply industry had arrived.
Development of national electrical power systems is still ongoing, however it should be noted that standardisation of voltage output and frequency remains to this day purely on a country by country or continental basis, and is by no means uniform across the world. This simple fact has wide ranging secondary effects, since electronic devices are particularly sensitive to differences in voltage and frequency.