Model:-35AGeneral:Name:Scientific Pocket CalculatorCode-Name:none (Classic?)Family:ClassicLogic:RPNFeatures:scientificFirsts:one at all (also: Classic, RPN, etc.)Introduction:Date:1972-07-01 (from wall of fame,possibly 1972-02-01)Price:$395Discontinuation:Date:1975-02-01Price:$195Production-Run:?Display:Type:LED, 7 segmentSize:1 line x 15 charsNumber-Formats:sign, 10 mantissa, ., exp sign, 2 expAnnunciators:...............battery low(true decimal has digit to itself)Data:User-Visible:Smallest:1E-99Largest:9.999999999E99Signif.-Digits:10Internal:Smallest:1E-99Largest:9.999999999E99Signif.-Digits:10Data-Types-and-Sizes:real, 7 bytesMemory:Named-Registers:X, Y, Z, T, SFlags:noneRegister-Usage:Z is duplicated into T after trig functionsNumbered-Registers:noneProgram-Steps:noneProgram-Editing:noneProgram-Display:noneUser-RAM-Bytes:35Total-RAM-Bytes:49ROM-Bytes:768 (10-bit words)Machine-State:prefix key statestack lift enableregisterstotal of 7, 7-byte registers and 12 status bitsFile-Types:nonePhysical:Technology-Used:?Processor:?Chip-Count:81820-0853 anode driver and system clock1820-0854 cathode driers1820-0855 clock driver1820-0849 CPU control and keyboard scanner1820-0848 CPU data1818-0024 ROM (256 x 10), 10-pin can1818-0026 ROM (256 x 10), 10-pin can1818-0028 ROM (256 x 10), 10-pin canPower-Source:3 nickel-cadmium AA cells, ACContinuous-Memory:noneExpansion-Ports:noneI/O-Ports:noneClock:noneLength:5.8 inWidth:3.2 inHeight:0.7 to 1.3 inWeight:9 ozTemperature-Range:Operating:0 to 40 deg CCharging:10 to 40 deg CStorage:-40 to 55 deg CKeyboard:Switches:OFF / ONShift-Keys:noneUser-Defined-Keys:noneKey-Arrangement::** ** ** ** **** ** ** ** **** ** ** ** ******* ** ** ***  *** *** ****  *** *** ****  *** *** ****  *** *** ***Key-Labels-Base-Keyboard:: y xxloglneCLR\v/xarcsincostan1/xx<>yRvSTORCLENTER^CHSEEXCLx-789+456x123\:-0.\piProgrammable-Operations::noneNon-Programmable-Operations::+addition-subtraction0-9, .enter digit or decimal point1/xreciprocalARC COSarc cosineARC SINarc sineARC TANarc tangentCHSchange signCLxclear XCOScosineEEXstart an exponent, 1 not requiredENTER^entere^xnatural exponentiationlnnatural logarithmlogcommon logarithmRCLrecall from registerRvroll the stack downSINsineSTOstore in registerTANtangentxmultiplicationx<>yexchange x and yx^ypower\:-division\piconstant, value 3.141592654\v/xsquare rootMenus::noneBugs/ROM-Versions::On early models, if you did:2.02lne^xyou got 2.  More fully, we have the text of an officialHewlett-Packard errata sheet:HP-35 ErrataExponential Functions1. This siutation involves the use of certain   numbers, which, when used as the value of   "x" in e^x, cause that function to give an-   swers that are off by a maximum of one   percent.   The numbers are 0.,7030975114 and   0.995033085 x 10^-2, or integer multiples   of the latter number though nine, by itself,   or when added to the former.  These num-   bers are correct when used by themselves   or derived as answers to expressions such   as ln 2.02 (ln 2.02 = 0.7030975114).  The   idiosyncrasy is in the e^x function, not the   logarithmic function.   Additionally, since x^y = e^yln x, when yln x   equals one of the numbers above, then x^y   will also be off slightly less than one percent.   To achieve a very good approximation of   the proper operation with these numbers,   you can simply leave off the last digit of   the number to be used as "x" in e^x or x^y.2. In e^x, when x = (-2291.072168 +/- 11.512924)   x 10^J (J can equal 0 through 96), the HP-35   will indicate overflow (9.999999999 x 10^99)   when it should indicate underflow (0).  The   numbers mentioned above are beyond the   dynamic range of the calculator.Trigonometric functions1. The HP-35 gives the following answers:arc sine 0.0002 = 5.729577893 x 10^-3arc cosine 0.0002 = 89.99427042arc tangent 0.0002 = 5.729577893 x 10^-3The correct answers are:arc sine 0.0002 = 0.01145916arc cosine 0.0002 = 89.98854arc tangent 0.0002 = 0.11459162. The HP-35 gives the arc tangent of   1.00020002 as 45; the correct answer is   45.00573.  This represents an error of ap-   proximately one one-hundredth of one   percent.3. There is a deviation of approximately one   one-hundredth of a percent in the arc sine   and are cosine of these numbers (arc   tangent is correct):0.70717748820.70717748840.70717748830.7071774885The HP-35 gives 45 for the arc sine and co-sine of these numbers; the arc sine should beapproximately 45.005730, and the arc cosineshould be approximately 44.994270.We are confident that this list represents therange of errors in the calculator.Hewlett  hp  PackardAdvanced Products10900 Wolfe Road, Cupertineo, CA 95014Try:0CHS\v/and you will get an error, even though it can take the square root of zero.These bugs _may_ have caused a recall.  Rumor.  Not confirmed.Notes::"Original" non-programmable hand held slide rule.  Had x^y not y^x!Price went down to $295 when the -45A was introduced.The trig functions compute in degrees only.The ROM was on three chips.  All are active and read the same (8-bit)address.  Only one is selected, and only that chip's data is returned.price changes:1973-05-01$2951974-05-01$2251975-02-01$195Early units had a small hole to the right of the ON/OFF switch.  Thishole had an "on" light, which is of course redundant.Very early units just had "Hewlett-Packard" with no model number.Early models had labels printed above the key, not molded into the keys.The story is that it was called the 35 because it had 35 keys.  Thelogic behind other calculator numbers is, shall we say?, less obvious.There is a rumor that 1 or 2 units were custom built with green LEDsfor either Carl Hewlett or Dave Packard.  The green LEDs drew muchmore power.------------------------------------------------------------letter from Jordi Hidalgo in DATAFILE V22 N1 p4, January/February 2003Quoted from HP-35 Math Pac manual, page 168:How would you display all 1's, 2's, ... 9's?1's: 9 e^x e^x 9     EEX 88 \:-2's: 9 e^x e^x 4.5   EEX 77 \:-3's: 9 e^x e^x 3     EEX 66 \:-4's: 9 e^x e^x 2.25  EEX 55 \:-5's: 9 e^x e^x 1.8   EEX 44 \:-6's: 9 e^x e^x 1.5   EEX 33 \:-7's: 7.777777777 EEX 78's: 9 e^x e^x 1.125 EEX 11 \:-9's: 9 e^x e^xThe author found a shorter way to do 7:7's: 9 1/x 7 EEX 78 *Tony Duell has a nice "HP-35 Internals..." article in DATAFILE V22 N6 P11.