Cheap Solar Cells and LCD

These produce almost no power.

Certainly not enough to run on eof these.

I was working on a similar project last year but on a much bigger scale (if that makes sense!) for products requiring small cells and larger flexible solar cells. After looking thru the websites of a few hundred solar cell and panel manufacturers and distributors (oh the internet is such a wonderful tool), I was able to narrow down the list to a few that you may find helpful.

And a distributor that may be helpful

I did not include the manufacturers that make the cells for those calculators as the MOQ is in the thousands. There should be other local distributors that stock some of these company's cells if you keep looking.

In the end, if you only want small quantities quickly, buying very cheap solar powered calculators may be a viable option (just make sure that the solar calculator is not a battery-powered calculator with a fake solar panel like the one I found!).

;)

Thanks Macgyver! This is good stuff.

Would this help?

Thanks for the link but I am looking for just the cells themselves to manufacture into a product. (indoor cells that operate under 200 lux)

Here is a solar cell I like, flexible thickness of a soda can with and a few other interesting features.

• * * Christopher

Temecula CA.USA

After measuring the output of these solar cells, I have to agree that you are correct.

How do they manage to run the solar calculator on a microamp budget.

The purpose-specific LSI chip is designed from the ground up to use very little current. Eg. JT6A72-CS Toshiba 8-digit calculator:

1.9uA wait/3uA operating typical @1.4V (it incorporates a charge-pump voltage doubler, so the actual current draw of most of the chip is half of that). This particular chip blazes at a mind-bending 18kHz when calculating and then throttles back to a more leisurely 7kHz when waiting for a keystroke. Current draw surges to 4uA (max) peak during the worst-case calculation (square root of all 9's) for a worst-case time of 263.2 milliseconds.

Typically, with solar power, possible excess voltage from the solar cell is clamped by an external shunt regulator LED.

Best regards, Spehro Pefhany

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"it\'s the network..."                          "The Journey is the reward"
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Spehro Pefhany wrote in news: snipped-for-privacy@4ax.com:

I found that 69 n! on a scientific 10 digit calculator makes it chew hardest, so if that function is available, it's fun to try. Newer ones do it fast though, the first one I tried was a Texas Instruments one in 1982 which took around 10 seconds or more.

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Yep, I had that one.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

I'd heard that some people loved their calculators, but I had no idea...

I think the TI-59 (the one with the magnetic card reader) was in that general range for factorials.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Whoa! My Casio fx-115MS (dual solar/battery) calculated 69! in a split second. 1.711E+98

70! results in a Math Error (overflow?)

Not bad for $15 at Target. (Used it for taking the PE exam - they have a very limited selection of allowed calculators.)

Michael

We were talking late 70's early 80's era calculators, with LED displays, not this newfangled stuff. The slowest calculator I've owned is a cute little handheld Commodore LED display unit (9V battery, PET style 'chiclet' keyboard). Tan(0.5) blanks the display for approximately 3 seconds. Chip is a MOS MCS7529 in white ceramic and gold package, with an ITT Led driver chip. Through-hole 0.1" pitch all the way.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Just tried the HP11/12C emulator I have here on my laptop. It calculates 1000! (4.024E2567) in well under a second. 1001 overflows (strange).

This one was free, but I doubt they'd let a laptop into the PE exam.

--
  Keith

I doubt it too.

I would have liked to just bring my old TI-85 to the exam, but I guess they didn't want me to copy down all the questions and re-sell them on the internet. (Like I'd have time to do that...!!!)

Annoyed me too, that they don't allow digital watches (!!??) - I had to buy a $6 "analog" watch from Wal-Mart to keep the time.

Michael

Spehro Pefhany wrote in news: snipped-for-privacy@4ax.com:

When it's all you have as a kid you make the best of these things. >:) I had one of those TI-59's once too, later, but I didn't make much use of it.

Another fun thing I used to do was take a constant multiplier like

2.1452767 and start with 1 or other seed value, and when it got to the top and overloaded, I'd press CE to let me carry on with the truncated value. I learned that you can get a chaotic, even random output if you chose good starting values, despite sticking to a rigid and repeatable set of rules. That experience helped me to understand a bit of chaos theory a few decades later, and also to make true white noise generators in FM synthesis on Yamaha SY99 and SY77 synthesizers.

Ok, it's true, I have LOTS of time. :) But when I see the way coding is getting in certain operating systems that should be nameless, and in some electronic hardware too, though to less extent, I think plenty of time and less money might do the whole industry a lot of good.

One thing I like best is the tiny answers to complex problems like the 'Best of EDN' circuits. It takes either a lot of inspiration, or a lot of testing time, to come up with stuff like that.

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Speaking of "chaos" from simplicity, have you ever heard of "the Mandelbrot set"? Actually, it's more merely "fractal" than "chaotic", I think. I found some examples here:

set%22

Cheers! Rich