15C Reissue is actually a carefully disguised printer?


This seems to have appeared, wonder how long it'll stay up. http://www8.hp.com/us/en/products/printers/product-detail.html?oid=5153395


Addition loop test, completed in HP labs. Up to 100X faster than original HP 15c. :-))


Assuming it uses the exact same emulator inside the latest version of the 12C+ -- I see no reason why it should not -- then it should run 150x faster than the original 15c.


What is the battery life on the 12C+ ?


What is the battery life on the 12C+ ?

So-so. Here are my approximate current measurements:

OFF = 0.004 mA
ON/idle = 0.05 mA
ON/running AMORT or tight loop = 20 mA

The two CR2032 cells have a combined capacity of about 450 mAh (depending on brand) at a standard current draw of 0.2ma. So the OFF state current draw is fine, implying a "shelf life" of 12 years.

The ON/idle state implies a lifetime of about 1 year, still pretty good.

However the running time is horrible, since the capacity of these cells drops precipitously beyond their standard rating of .2 ma. Manufacturers don't rate these to work at 20ma, so I can only guess (or test, I suppose) the capacity at 20ma. If I had to guess I'd say it's about 40mAh. Giving the calculator about 4 hours of continuous run-time use -- it might be less than this.

If you're not running "loopy" programs however, the quick 20ma current burst won't kill the batteries nearly as fast as a continuous draw. So basic math functions should allow for decent battery life.


Edited: 24 Aug 2011, 12:15 p.m.



I enjoy reading your posts. Can you give us a rough estimate (years?) for "decent battery life", and without me having to search the forums, can you tell us the estimated battery life of the original 15c or 12c?

I am wondering how close the old and new compare for folks who do not run "loopy" programs.



Measuring an original 12C I get these approximate current measurements:

OFF less than 0.0001 mA
ON/idle = 0.01 mA
ON/running AMORT or tight loop = 0.4 mA

If the calculator is powered by Energizer 357 (silver oxide) cells that are rated at 150mAh at .2ma current draw the OFF state will be dependent only on the battery self-discharge. For silver oxide cells this can be 20 years at room temperature or maybe 50 years at zero Celsius. ON/idle state will be about 1.5 years similar to the 12C+, the big difference is when running long functions or loops.

The 12C can run for around 300 hours before exhausting the cells, while the 12C+ is only good for a few hours at best. Of course the 12C+ runs 150 times faster so the number of execution steps per set of batteries is about the same, surprisingly (or maybe not).

I can't really give an estimate on how long a set of batteries will last in either calculator under normal conditions unless those conditions are defined carefully. But from the above it seems pretty clear that if you do the same functions on a 12C and a 12C+ you can expect similar overall battery life.



What does this mean? Is it just an emulation or an improvement?


On the 15C produced from 1982 through 1989, the memory pool included 67 total registers, RI, R0, R1 ... R65. Registers RI, R0, and R1 could not be allocated to program storage, but the remaining 64 (R2 ... R65) were allocatable between data and program storage. Each numbered register (above R1) could be converted to 7 bytes of program memory. At power up, the memory pool was split such that there were 21 data storage registers (RI ... R19) and 322 bytes of program memory (7 bytes each for R20 ... R65.) Since the highest numbered register was called R65, the specification for 65 registers appears to be consistent with the capabilities of the original 15C.


Edited: 24 Aug 2011, 8:58 a.m.


It's both.


My understanding is the new calculator emulates the function of the old one exactly. The improvement is the speed increase.


HP made an HP 15c iPhone app available in 2009 or so. Hopefully, the code had been debugged and can easily be implemented in the 12c+ hardware.



When i discovered the hp calculator emulator apps for the iphone they didn't have good reviews compared to the "aftermarket" emulators. So i went with all "aftermarket" emulators and have no complaints.


I wanted to see what a close to true 15C was like so I ponied up for the HP iPhone 15C. I never had a real one to compare it but I'm guessing all the functionality is there.

My 1 real beef and the reason I don't use it more is that the keyboard click is so loud it is annoying. There is no way to turn it down other than turning the whole sound down on the phone but this affects the ringer which I need up due to where I work.

The other complaint I have read is that while it says it contains a manual, it only contains the first half of the manual and ends before the programming section.

My Go-To iPhone calculators are the i41CX+ and Free42 except when I need to graph something and then I use PocketCAS lite.


It comes with the 15C emulator on CD, too. Odd place for this to show up.


*If* it comes. I hope it is already in production.


Perhaps calculators are being moved to the printer division under the new HP organization ?


LOL! Now there's a rumor for you!


That link is still up as of August 28th. There's no doubt that people on the inside have been made aware of it. You'd think it would have been taken down by now if it were a mistake. I'm probably reading too much into this, but it makes me start to wonder if there is truth in the idea that calculators may be moving under printers at HP. That would be tremendously good news, since printers are presumably still very profitable and more likely to be resistent to spin-off.

15C specs listed under printers


It may also explain Tim's more blatant candor about the HP-33s and HP-35s.


The 12C 30 year anniversary is showing available 9/1 NW258AA#ABA

12C 30 years


Nice ad. The model should have worn some kind of lab dress and presented the 15C LE ;-).


That link is still up as of August 28th.
Not only is it still up, but the display content of the 15C LE changed :-).


Looks like somebody listens :-)


Yeah... looks like they fixed the rounding error on pi.


Got to hand it to those responsive people in the printer group.



They must be a big help to you personal systems guys. Perhaps they have body doubles too? :)


I'd say the liberal arts majors and MBA's running HP have pretty much run HP into the ground. :-(



I'd say the liberal arts majors and MBA's running HP have pretty much run HP into the ground. :-(


Hey! Some of us MBAs are doing everything we can to keep it afloat. Don't bite the hand that feeds you ;)


Yeah... looks like they fixed the rounding error on pi.

The 15C LE may not be so fast after all, it took a while to calculate the 9th digit of Pi after the decimal with the right accuracy .... :-)


It was the carrier pigeon network probably. Took a while to get there.


Edited: 31 Aug 2011, 10:46 a.m.


ooh, I always thought you rely on floo powder ...


ooh, I always thought you rely on floo powder ...

ROHS restrictions took care of that.


The link under printers is no longer there since the HP-15C LE is now officially listed under the scientific calculators section.

Official HP-15C LE link


As long as printers are supposed not to be axed (like PCs and notebooks, as per last week news), it may be a good thing to consider these calculators as "printers". Even the HP 41 or 42 may be considered "IR printer controllers" or "IR print servers".


If they bring back the 42S, add WiFi and a gig of RAM, there's no reason it couldn't be quite a capable print server.

02>LBL A
04 PRA
05 FC? 1200
09 GTO A
10 "Print job complete"
12 .END.

Honestly I don't care if calculators become part of the rubber chicken division as long as they keep making them ;-)


That would be an awesome business card.



Actually, you could probably pull that off as I suspect you have a pointy haired boss somewhere up the ladder who would believe that RCD meant Research into Calculation Division, but the rest of us would know and your business Card could tell the real story.

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