## the photovoltaic effect

Albert Einstein is most commonly known about his theory of relativity, particularly the mass energy equivalence, E = mc^2. What most people don’t know is that Einstein conducted the most comprehensive theoretical work on the photovoltaic effect, which means turning light into electricity. In fact in 1921 Einstein won the Noble Prize for his explanation of photovoltaics. Einstein explanation stated that light was a stream of particles, called photons. His studies suggested that when you shine a light upon certain metals, a stream of particles, electrons are emitted from the metal. Einstein concluded in his studies of the photovoltaics: the number of electrons emitted depends on the intensity of the light beam. electrons move faster if the applied light has higher frequency. light has to hit the threshold frequency before electrons can be generated. Many physicists were perplexed because they thought of light as a wave, not a stream of particles. Although Einstein proved that light has a dual nature, it can act both as a wave or a stream of particles depending on the conditions. Looking back at history the first discovery of the photovoltaic effect happened back in 1839, so why are we still so behind in terms of adopting solar photovoltaic panels in our daily lives? It seems like the world has known about photovoltaics for such a long time but has not moved forward aggressively enough to take full advantage of the largest energy source known to man, the sun. Do you think photovoltaics is one of society’s best kept...

## whats the deal with open circuit voltage?

I want to talk about Open Circuit Voltage (Voc) since I know this important electrical rule is not understood by most people who buy solar panels. For example, lets say we have a nominal 12v solar panel and you take it outside on a sunny day without a load connected to the solar panel and test the voltage. The results might surprise you, if you don’t understand Voc since the voltage will read higher than the nominal or “rated voltage” on the solar panel. Voc is the maximum voltage a solar panel is able to output when there is no current flowing through the solar panel, once you connect a load to the solar panel, the voltage will decrease closer to the nominal voltage. This is one of the basic building blocks of understanding how solar panels work, so I hope you got some value out of this short explanation. Does open circuit voltage make...

## the simplicity of enphase mirco-inverters

I was on enphase energy’s website reading their case studies today and was amazed by the simplicity of Sreenivas family’s 2.3kW solar electric system using enphase micro-inverters. The system is made up of 13 sharp 175w solar panels which are connected to each other via AC interconnect cables that are already part of the enphase mirco-inverter. 12/3 romex is used through the garage attic from the solar array to a 1-15 amp backfed breaker in a 100 amp main panel. The Sreenivas family case study is a good example of how enphase makes deploying solar panels an easier process by avoiding stringing solar panels which has a direct impact on system complexity and how long it takes to install a solar electric system. The enphase micro-inverter is more then a grid tie inverter, they’re an “inverter solution” since performance monitoring is built into the system and is the only grid tie inverter that can monitor the system down to the individual solar panel. This installation looks quite simple, don’t you agree? What do you think about solar electric systems that use micro-inverters versus a traditional centralized inverter? Enphase Diagram of Sreenivas...