A lot of time we are asked what is the equivalent LED product to convert from Metal Halide, High Pressure Sodium or Mercury Vapor. And a lot of time, we have a product in mind that works based on past experience. But how did we come up with that product, and how did we make the original decision on what was the proper replacement?

There’s a lot of science that goes into light, color, quality, and each light had it’s own characteristics. For example, it takes less LED to replace High Pressure Sodium than it takes to replace Metal Halide. And we are talking a lot more than just lumens. We are talking about color temperature, quality of light and something called photopic / scotopic lumens.

In the world of lighting, we measure foot candles with a light meter, this is called a photopic measurement. The light meter picks up everything, including spectrum’s that are invisible to us. Now, we humans see things to, and this is called scotopic lumens. Our rods and cones read and interpret light. And it does so differently than what a light meter does. So it is not uncommon when we demo a LED Light against a HPS light or Metal Halide, we first ask “Which is brighter” before we show the light meter reading. It leaves a few people scratching their heads. Well, that’s the science of of it all, and fortunately there is some handy tables called SP ratios that allow us to take the lumens of a particular light (photopic lumens) and multiply it by the S/P ratio to get the scotopic lumens equivalent.

For example, the S/P ratio for High Pressure Sodium is 0.40. The S/P ratio for LED at 5000K is 1.8. So if you take 40,000 lumens of HPS and multiply it 0.4, the effective scotopic lumens is 16,000. To get the same amount of lumens from LED, take the 16,000 and divide it by the S/P ratio and you get 8888 lumens. So the 8888 lumens of LED is the photopic measurement, the 16,000 LED lumens is the scotopic lumens measurement. So in an nutshell, you need 8,888 lumens of LED to replace 40,000 lumens of HPS from a scotopic point of view.

Here is a handy chart of common lights and ratios for you to use.

Electrical transformers are machines that transfer electricity from one circuit to another with changing voltage level but no frequency change. Today, they are designed to use AC supply, which means that fluctuation in supply voltage is impacted by the fluctuation in the current. So, an increase in current will bring about an increase in the voltage and vice versa.

Transformers help to improve safety and efficiency of power systems by raising and lowering voltage levels where needed. They are used in a wide range of residential and industrial applications, primarily and perhaps most importantly in the distribution and regulation of power across long distances.

An electrical transformer uses Faraday’s electromagnetic induction law to work – “Rate of change of flux linkage with respect to time is directly proportional to the induced EMF in a conductor or coil”.

Anyone who has ever tried to plug in an appliance only to find that it wouldn’t turn on is familiar with how frustrating electrical outlet wiring problems can be. The whole purpose of having outlets is the convenience, but that goes right out the window when they stop working without warning. Although a dead outlet might automatically seem like a big problem, sometimes it can be due to a simple issue. This isn’t always the case, of course — sometimes there will be electrical outlet wiring problems that can only be addressed by a professional, particularly when the issue is with your outlet’s wiring.

You might be able to save yourself a call to an electrician if your outlet problem is something easily fixed. You can even resolve some minor issues without the use of tools! If you know what steps to take, you may be able to figure out if the dead outlet is something you can remedy yourself. If you discover the problem is something that should be handled by a professional, don’t take any chances. Messing around with wiring can put you in danger and damage your electrical system instead of making the problem go away.

A simple issue can quickly turn into a very expensive one if you aren’t careful. Here are some easy things to try that won’t put you in any danger: