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How to Select the Most Appropriate Indoor LED Bulb Color

2021-10-18

Pinzheng Furniture

The pictures you supplied as an example represent unnatural colors in a forest being highlighted by artificial lighting. What you ask for and then show seems to represent two different things.Sometimes you have to buy a 3000k, 3500k, and 4100k bulb and see what works best for the location. Too low of color temperature and the whites in those pictures will fade, too high the whites will offend. The CRI (color rendering index) plays a difference too, if you have the option to pick a higher CRI the colors will be less distorted. A little history, if go back to an era that electric lighting was just Edison bulbs people picked colors of walls, flooring and furniture that created a comfortable look with the available lighting. When fluorescent lighting became available the initial locations for use was in warehouses and other commercial settings where color was less important than efficiency and often the greys and browns in a industrial setting worked better with a lamp that was more blue (4100k) than an Edison bulb. When one of those blue cool white bulbs is used in an environment with colors picked for Edison bulbs too much blue becomes highlighted in the space, and a warmer (3000k) color was developed to more closely create a similar effect as 2700K Edison bulbs.3500K is usually a pretty good neutral color, but we do not always decorate in the sames colors as 1950 so you have to look at your own interior colors. One house I lived in had kind of creamy tan carpets, matching paint, pine color cabinets and similar colored counter tops. The warm white lamps made it look dingy, 5000K lamps pulled the lighter tones out and made it more comfortable. House I live in now has all white baseboards, doors and casings. A 5000k lamp would make the the whites pop, and finger prints stand out. Also if somebody puts makeup on in a 5000k bathroom the goes to work in a 3000k office they may always look jaundice because they put too much yellow makeup on, or if they use a 3000k bulb for makeup and work outdoors they may look pale. You really need to light the room for it's use and colors.

1. Can I install a 100W LED bulb in a car?

I am going to assume that you are referring to 100/130W equivalent bulbs, not that they draw that much current. As long as the current draw is less than the stock bulbs you should be fine.Years ago I updated the 55W bulbs on my 525i to 80W bulbs and the additional current draw was enough to melt the wiring at the bulb. Those bulbs were actually drawing 80W, hence the melting. But LEDs generally consume less power for the same light output, so replacing conventional bulbs should not require any changes to the wiring

2. Light intensity is dropping on large LED bulb display when it sequences

R52 and R55 are too large. With 24 big LEDs in parallel, you need 3 amps from your 12 volt supply. Call it 1.5 amps per PNP transistor. Because you want the PNPs to be hard on ("saturated" is the term), you should provide about 150 mA of base drive per transistor. That is, a good rule of thumb for transistors in saturation is that they are operating with a current gain of 10. Assuming 10 volts across the base resistors, they should be about 10 / .15, or 67 ohms. The value is not critical, so 50 to 100 ohms will probably work. And smaller is better. And make sure they can handle the power - use 2 watt resistors at a minimum. The 1k value which I recommended in your previous version was adequate for the much lower current requirements of your smaller LEDs, but not for these piggies. To put it another way, with 1k base resistors you get about 10 mA of base drive. If you assume a gain in the PNPs of 100, that only provides 1 amp per transistor, rather than the 1. 5 you need. Which is why the circuit works OK with only a few LEDs on - they are not drawing much total current.Note that this means your 12 volt supply should be rated for at least 4 amps. And you can get rid of the new caps, too. If anything, they add to the current requirements when the transistors first turn on.EDIT - And, of course, I did not think things through. A second problem is R51. As with R52 and R55, this is sized for a lower current draw. As given, a 1k R51 provides about 4 mA of base drive to the TIP31. Since the NPN also should be in saturation, this only provides for 40 mA of solid base drive to the PNPs, when they need 300 mA. Fortunately, the Arduino IO lines are rated for 40 mA of source drive, although the voltage output at this current level is not specified. The NPN needs 30 mA of base drive, and let's figure on 4 volts output at this level. Then 3 volts will be dropped by R51, and 3 /.03 equals 100 ohms. So replace the 1k R51 with 100 ohms and see what happens. My apologies for not thinking this through.END EDIT

3. Strange behaviour of a LED bulb via SSR Relay: it's EMI?

I do not know what kind of electronic testing equipment you have. Basically you will want to put a low pass filter on the power line tuned between the primary frequency and the second harmonic. Better would be to put a band pass filter at the power line frequency, a tuned circuit at the power line frequency. But that is a real pain to get adjusted properly without a frequency counter and the lower frequencies are probably not causing the problem. Ferrite are fine, but put many turns of wire around and through the ferrite to increase the inductive reactance. If you know a ham radio operator, you can ask for assistance in choosing the components for a good filter. The ham may even have the diagnostic tools to help diagnose and fix the problem

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