Who knew?

[Ev in Oregon]

Yesterday I replaced all the old-style bulbs in the fixtures in my Bigfoot with LEDs. What a difference! But, that isn't what this discussion is about.

I just discovered that my hand-held solar calculator doesn't work with LEDs. I had to position the calculator under a small lamp with a regular bulb before it'd light up.

Maybe some of you in-the-know folks could explain why?

[Raz]

Originally Posted by Ev in Oregon

Yesterday I replaced all the old-style bulbs in the fixtures in my Bigfoot with LEDs. What a difference! But, that isn't what this discussion is about.

I just discovered that my hand-held solar calculator doesn't work with LEDs. I had to position the calculator under a small lamp with a regular bulb before it'd light up.

Maybe some of you in-the-know folks could explain why?

Most calculators use Liquid Crystal displays. While LED's are efficient they still draw power, more than a small solar cell can provide. LCD's rely on reflected ambient light and use virtually no power at all. Raz

[Ev in Oregon]

Thanks for the explanation, Raz. I try to learn something new every day -- this was it for today!

I figure by the time I'm 100, I'll be as smart as I was when I was a teenager.

[Donna D.]

Originally Posted by Ev in Oregon

I figure by the time I'm 100, I'll be as smart as I was when I was a teenager.

Diet Coke just shot out of my nose

[Lis in RI]

I figure by the time I'm 100, I'll be as smart as I was when I was a teenager.[/QUOTE]

Some time ago I was at a roadside dinner. on the counter there was a sign, "Hire a teenager while they know everything".

[papa-t]

Yea what he said. Makes my head hurt ��

[John Linck]

My favorite


“When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty-one, I was astonished by how much he'd learned in seven years.” Mark Twain

[honda03842]

Re-learning the 14 to 21 lesson.

I have an older friend, Tony, in our Escapee Park that I have written about in the past. Tony is a very healthy 82 and spent 15 years full-timing.

I emulate Tony in many ways. Like Tony I faithfully do my morning exercises and often take a short after lunch Tony, a nap. Many mornings I walk 3 loops of the park with Tony sharing opinions on the park and the world. Our opinions often are not the same.

Yesterday while in a private moment on an interesting tour of an orange orchard I told Tony "though we sometimes have different opinions that I always appreciate your sharing of 'well considered' opinions".

I recognize that his additional years of experience is valuable and that sometimes it takes me years to recognize I was wrong about this or that. As well telling some one you appreciate them or their thoughts is important, a little 'I Love You' goes a long way.

[Paul O.]

Originally Posted by Ev in Oregon

Yesterday I replaced all the old-style bulbs in the fixtures in my Bigfoot with LEDs. What a difference! But, that isn't what this discussion is about.

I just discovered that my hand-held solar calculator doesn't work with LEDs. I had to position the calculator under a small lamp with a regular bulb before it'd light up.

Maybe some of you in-the-know folks could explain why?

Here is the story: the calculator uses a solar cell to get its power. Sunlight and incandescent light is broad band, including infrared, and the calculator gets enough power from it. LED's are efficient, narrow band light sources. Even the new "white light" LED's are emitting very little energy in narrow red, green, blue bands. So you get white light, but not much energy out of it. That is the key to the power savings you enjoy with the LED's. (In a simplistic way - less power in, less power out.)
Paul

[tractors1]

Originally Posted by Paul O.

Here is the story: the calculator uses a solar cell to get its power. Sunlight and incandescent light is broad band, including infrared, and the calculator gets enough power from it. LED's are efficient, narrow band light sources. Even the new "white light" LED's are emitting very little energy in narrow red, green, blue bands. So you get white light, but not much energy out of it. That is the key to the power savings you enjoy with the LED's. (In a simplistic way - less power in, less power out.)
Paul

Agree with Paul - on a business trip I recall running a calculator at a dinner meeting by the light of another engineers cigarette lighter as the room lighting didn't provide enough juice.
Charlie Y

[Raz]

Originally Posted by Paul O.

Here is the story: the calculator uses a solar cell to get its power. Sunlight and incandescent light is broad band, including infrared, and the calculator gets enough power from it. LED's are efficient, narrow band light sources. Even the new "white light" LED's are emitting very little energy in narrow red, green, blue bands. So you get white light, but not much energy out of it. That is the key to the power savings you enjoy with the LED's. (In a simplistic way - less power in, less power out.)
Paul

I assumed Evelyn was asking why her calculator didn't use an LED read out. But rereading it I think Paul's interpretation is correct. That said, my solar calculator works fine under a White LED. Unfortunately I have no idea which technology my LED light uses. Some white LED's use blue with a yellow phosphor and some are a combination of Red Green and Blue. Perhaps others can try their solar calculator under a white LED and report back if it works. Raz

[Ev in Oregon]

So, when I turned on my radio this morning to listen to the news, I got such a loud buzzing noise that I had to turn it off. I had the kitchen light on (with the new LEDs), so I turned it off & the buzzing stopped. Tried it again, same result.

Luckily, my laptop doesn't seem to be affected by LED orneryness, so I got to listen to the news after all.

I'm easily entertained, so this has been kinda' fun, actually!

[Raz]

Originally Posted by Ev in Oregon

So, when I turned on my radio this morning to listen to the news, I got such a loud buzzing noise that I had to turn it off. I had the kitchen light on (with the new LEDs), so I turned it off & the buzzing stopped. Tried it again, same result.

Luckily, my laptop doesn't seem to be affected by LED orneryness, so I got to listen to the news after all.

I'm easily entertained, so this has been kinda' fun, actually!

Most electronic devices today contain oscillators. You will find them in calculators, computers, converters, just about everything. These circuits can produce electrical noise that can propagate for a very short distance. They are like little radio stations only instead of music the just make noise. A portable AM radio placed in close proximity will identify which devices have them. If you have young children in your life, it makes a fun game.

In regard to your original question, I tried half a dozen LED light sources; puck lights, mighty lights, flash lights, some cool white and some warm white and two solar powered calculators. Both calculators works fine with all the lights. I can not reproduce what you described. Sorry, Raz

[tractors1]

Some LEDs do cause interference with reception on nearby AM radios. The only solution is to try another brand.

Charlie Y

[Raz]

Originally Posted by tractors1

Some LEDs do cause interference with reception on nearby AM radios. The only solution is to try another brand.

Charlie Y

I think the regulators are all switchers and that's what causes the RFI?? Raz

[Terry G]

Originally Posted by P. Raz

I think the regulators are all switchers and that's what causes the RFI?? Raz

Many LED bulbs have a regulator electronic circuit which controls the current. The LED's will work off almost any voltage but the current has to be within a specific range. And yes, these circuits are usually switchers, which are very efficient. The circuitry is continuously switching between an off state and and an on state and the frequency of the switching can be anywhere from 50 kHz – 1 MHz. If the circuit isn't very well shielded, then the switching frequency (or one of its harmonics) can fall right in the middle of a radio band. In many instances the Chinese electronics manufacturers can turn out well-engineered, high-quality goods. And sometimes it's absolute crap. You pays your money and you takes your chances.

[LeonardS]

In the old days, current to LEDs was controlled by a resistor in series with the LED. But that was a waste of energy, as the resistor also consumed current. With the advent of itty bitty little switching transistors (IGBTs) and supporting circuits, the power consuming resistors are replaced with the switching transistors. As you've noticed, the switching action can cause electrical noise. In my day job we have to deal with this, as folks are changing out regular bulbs for (sometimes) noisy LEDs. In our case it is usually more annoying than a radio making strange sounds, sometimes it is a networked device not working correctly. Like a door not opening at the right time, or such. It took us a while to identify the culprits but now it is one of the first things we check for... a newly added LED circuit.


Sent from my iPhone using Fiberglass RV

[Ev in Oregon]

I probably should've mentioned first time around that the solar calculator I have is close to 30 years old (but up until switching out the old light fixture bulbs for LEDs, it's worked like a champ). I tried it again today indoors under the LEDs, then outdoors in the sun. It worked outdoors, but not indoors.

Also, the radio I was trying to listen to is about 6 mos. old, & I had it tuned to an FM station (NPR). I didn't try AM.

Boy, there sure are a lot of well-versed folks on this forum. I've learned a lot; now if only I can remember it all for longer than a couple days. Thanks!

[EcoHeliGuy]

Also you can't wire in series most LED lights. They don't pass enough current. You need to wire them in parallel. Keep this in mind if your installing led strip lighting.

On a side note if you have an iPhone. Try using the flashlight function on a calculator. The LED is powerful enough to run mine. Even moves those dancing desk ornaments.


Sent remotely

[TomK]

iPhones have a built in calculator. It's two icons to the right of the flashlight on the quick access slide up screen.

Tom