After Thomas Edison figured out how to mass produce the light bulb and keep it affordable his next task was to figure out how to get it accepted into people’s homes.  Edison’s brilliance lay in his uncanny ability as a marketer and practical applications engineer and he’s known today as a true genius because of the society changing concepts he implemented – they were nothing short of profound.

In those days light in the home was created with fire: gas lanterns and candles being the predominant means of lighting.  The infrastructure for gas lighting in cities was extensive and run by powerful companies who had no intention of letting some upstart like Edison ruin their business with a light that did not need gas – but we all know how that turned out in the end.

Edison was a clever tinkerer and a master at leveraging existing technology to his advantage.  With the financial help of JP Morgan and the Vanderbilts, Edison began building his infrastructure to light up homes in New York at a price competitive with gas lanterns.  The streets of New York were torn up and underground wiring was installed to feed the larger buildings with power that would operate light bulbs.

Power was generated by large dynamos driven by steam engines and coal.  The dynamos were big versions of the same kind of generator you might have used to power the light on your bicycle – you know, the one that rubbed against the bike’s tire.  The business started slowly but soon started to take off and gain in popularity.

Homes were first because the wealthy home owners were eager for something new and interesting as well they were concerned about the ever present danger of fire and the smell of the gas lanterns – a problem that the new light bulb didn’t have at all.  But soon a problem cropped up that was unanticipated.  As more homes were added the amount of light coming from the bulbs began to grow dimmer and those who found themselves the furthest from the generating stations had much lower light output than those of their uptown neighbors.

To make matters worse tall buildings, of which there are many in New York City, had the same problem as did the neighbors: rooms at the top of the building were noticeably dimmer than those at the bottom.  Businesses were excited to use the Edison light bulb in their office buildings but acceptance was limited due to the variability of the light output.

To solve the problem Edison built more generating stations which helped the neighborhood problem but nothing he did could tackle the tall building problem.

What was  the fundamental issue?  Edison was using DC to power his bulbs.  DC, or battery voltage, delivers exactly what the bulbs wanted but the amount of DC voltage was what controlled the brightness of each bulb and this is where we get in trouble.

Tomorrow, the problem with DC.

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