Retro Review: Radio Shack EC-4018

 Retro Review:   Radio Shack EC-4018

HAPPY NEW YEAR!

Quick Facts:

Company:  Radio Shack

Model:  EC-4018

Equivalent of:  Casio fx-470

Type:  Scientific 

Years:  Late 1980's

Display:  10 digits

Batteries:  Solar

Memory Registers: 1

Keyboard

The keyboard of the EC-4018 is a folding landscape.    The top half has the screen and 18 gray keys (scientific) to the right side, and two solar panel strips to the left.  The bottom half has 15 large black keys (arithmetic).  I really like the large keys on this calculator.  The keys are really easy to press and operated, and they also have a nice feel to them.  

Features

*  Trigonometric functions, logarithms, powers, rots

*  Convert to and from degrees-minutes-seconds

*  Four base conversions:  binary, decimal, octal, hexadecimal

*  Boolean Algebra: AND, OR, XOR, NEG

*  Fractions, combinations, permutations, reciprocal, factorials of integers

Physical Constants

INV 1:  Speed of Light in a Vacuum: c =  299792458 m/s

INV 2:  Planck's Constant:  h = 6.626176 * 10^-34 J s 

INV 3:  Universal Gravitational Constant:  G = 6.672 * 10^-11 N m^2/kg^2

INV 4:  Elementary Charge:  e = 1.6021892 * 10^-19 C

INV 5:  Electron Rest Mass:  me = 9.109534 * 10^-31 kg

INV 6:  Atomic Mass Unit:  u = 1.6605655 * 10^-27 kg

INV 7:  Avogadro's Constant:  Na = 6.022045 * 10^23/mol

INV 8:  Boltzmann Constant:  k = 1.308662 * 10^-23 J/K

INV 9:  Molar Volume of Ideal Gas:  Vm = 0.02241383 m^3/mol

According to the Casio fx-650 manual, these values are based on 1978 Japan Industrial Standards.  

The nice thing is that the units are stated next to the symbol.  

Verdict 

I am really like the keyboard and the contrast of the font colors.  The bright orange and gold really stand out against the black keyboard.   The screen's digits are really nice and big.  As I mentioned before, the keys have a nice feel.  

If you like a folding scientific calculator, you are going to have to search for a vintage calculator.  The good thing about Radio Shack is that their calculators tend to be less expensive than Casio.  

Sources:

"Electronic Calculators"  epocalc.net  Last Updated April 25, 2013.  http://www.epocalc.net/pages/mes_calcs_03.htm   Retrieved December 12, 2020.

Casio fx-650 Operation Manual

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Canon Palm Printer P1-DH V

Retro Review:  Canon Palm Printer P1-DH V

Quick Facts:

Model:  Palm Printer P1-DH DV
Company:  Canon
Type:  Printing
Years:   I think this model is around 2016, not sure, I got this from a search on Amazon.  The current version is P1-DH V3
Display:  12 digits
Batteries:  4 AAA Battery and/or AC Adapter AD-380
Original Retail Price:  about $30.00 to $35.00
Logic:  Chain

This review is on an older model P1-DH DV.  I think the current version at the time of this post is the P1-DH DV3. 

I will focus my review on the keyboard and features only, not on the printing features. 

The calculator will operate on AC power alone, without batteries, which I like. 

Unlike most printing calculators, the P1-DH V operates as a four-function Chain calculator instead of an adding machine.  For example:  to add 2, 7, and 11, type:

2 [ + ] 7 [ + ] 11 [ = ]

Result: 20

Features

This is a standard printing calculator that has the following features:

*  Decimal Point Selectors:  F (float, no indicator), 0, 2, 3, 4, A (add mode).  The mode is changed by the key [DEC].   Float is the default mode. 

*  Rounding/Truncate Toggle:  toggle between rounding and truncate with the [5/4] key.  When the 5/4 is on, the calculator is on rounding mode.  Note that this setting has no affect on results on when the decimal point selector is set to Float.

Example:

Float Mode:
1 [ ÷ ] 6 [ = ] returns 0.16 666 666 666

2 Decimal Place Mode:  (2 indicator)
5/4 on (Rounding mode):  1 [ ÷ ] 6 [ = ] returns 0.17
5/4 off (Truncate mode):  1 [ ÷ ] 6 [ = ] returns 0.16

*  One memory register is available, with sum and difference.   When [ M+ = ] is pressed, the calculation is completed and is added to the memory register.   When [ M- = ] is pressed, the calculation is completed and is subtracted from the memory register.

Example:

1000 * 298 + 928 * 172 - 442 * 180

[ RM/CM ] until memory is cleared
1000 [ × ] 298 [ M+ = ]
928 [ × ] 172 [ M+ = ]
442 [ × ] 180 [ M- = ]
[ RM/CM ]
Result:  378,056

*  Time Calculations:  You can enter hours-minutes for calculations in either AM/PM or 2400 hour format by using the [TIME CAL] key.  You know the calculator is ready to accept hours-minutes when the screen shows 00:00.  In AM/PM mode, switch between AM/PM by use the [TIME CAL AM/PM] button.  To calculate the difference between times, the required key is the key with the tilde mark on it.  ( [ ~ ] )

Example:  What time has passed between 23:17 and 11:16?  (2400 hours)

[TIME CAL] [TIME CAL] (00:00 without an AM/PM indicator means 2400 hours):
2 3 1 7 [ ~ ]
1 1 1 6 [ = ]

11:59 (11 hours, 59 minutes)

* Cost/Sell/Margin and Sales Tax Calculation.  See the next section.

The [ B ← → T ] Key

The [ B ←→ T ] rules what functions the blue keys execute on the P1-DH V. 

Indicator T:  Tax Mode (Default mode)

[ TAX+ ]:  Add tax using the rate stored
[ TAX- ]:  Subtract tax using the rate stored
[ RATE ]:  Press this key to enter the tax rate (RATE will be blinking), press [ RATE ] again to finish

Indicator B:  Business Mode

[ COST ]:  Cost
[ SELL ]:  Sell
[ MARGIN ]:  Margin

Enter any of the two values, the third is automatically calculated.

Example: 
Sell = $29.95,  Margin = 8%

[ B ←→ T ] until B appears
29.95 [ SELL ] (SELL flashes)
8 [ MARGIN ]

Result:  27.55 (COST indicator)

Keyboard

The keyboard is nice and light.  The keys are rubber and very responsive.  The key response and register is great.  My hands are a little too big but it is possible to speed calculate on the Palm Printer. 

I like the screen but I wish the indicators were bigger, as they are too tiny for my preference.  Just make sure you triple check which mode you are in.  This model I purchased in December 2019 at a Revivals Store in Palm Springs. 

Eddie

All original content copyright, © 2011-2020.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Retro Review: TI-30 (1976)

Retro Review:  TI-30 (1976) 

One more quick blog posts before I head off into surgery this week.

Quick Facts

Model:  TI-30
Company:  Texas Instruments
Type:  Scientific
Years:  1976-1982
Display:  8 digits, 5 digits with 2 digit 10^xx in scientific notation, red LED lights
Batteries:  Battery, 9 V
Original Retail Price:  $24.95
Logic:  AOS (Algebraic)

History

The TI-30 is one of the first scientific calculators to cost less than $50.00 retail, making one of the first scientific calculators to be sold to a wide audience.

The TI-30 model name is carried to present day, with the latest incarnation being the TI-30xa with a gray keyboard and wide digit display.

TI-30 from 1976 (left), TI-30Xa from 2015 (right)

Features

The first TI-30 is a simple, basic scientific calculator.  It's features include:

*  Trigonometric functions and inverse
*  Logarithmic functions and inverse
*  Powers and Roots
*  Parenthesis
*  One memory register with sum and exchange commands
*  Arithmetic, percent, reciprocal

There is a DRG key where it cycles through Degrees mode, Radians mode (indicator of I), and Gradians mode (indicator of II).

Buyers had an option of purchasing one of three carrying pouches to carry the TI-30.  The one I purchased on eBay had a denim carrying pouch and it's really nice!

The display had a few indicators which was pretty advance for its time:

When a calculation is in progress, the right-most digit displays a "twirling eight".

If an error occurs, the word "Error." is spelled out.

If the calculator is left on for a few seconds, it goes into a screen saver mode.  The screen saver has a decimal point scrolling across the screen left to right.  This is designed to save battery usage.

The TI-30 also had a power adapter, I would imagine that those would be hard to find today. 

Keyboard

I am very pleased with the keyboard:  the keys are well maintained.  The keys are easy to press.  The LED screen is clear and easy to read.  The keys are responsive, don't just try to be a speed typist and everything will be fine.  The calculator is nice and lightweight.

The only thing I had a hard time with was trying to attach the 9-V battery and closing the case.

Verdict

I'd say yes; if you are a calculator collector, it is worth collecting, even if it is only historic value.  It also doesn't cost too much, I paid $17 for mine. 

Routine Goodies

Absolute Value:  | n |
n  [ x^2 ] [ √x ]

Sign:  sgn(n) = -1 for negative, 1 for positive (does not work for n = 0)
n [ STO ] [ * ] [ x^2 ] [ √x ] [ ÷ ] [ RCL ] [ = ]

Modulus:  n mod m  with n > m, n > 0, m > 0.
n [ ÷ ] m [ STO ] [ = ] [ - ] (integer part of the result) [ = ] [ * ] [ RCL ] [ = ]

Convert to Scientific Notation:
[ * ] 1 [ EE ] [ = ]

Convert to Floating Numbers:
[ * ] 1 [ INV ] [ EE ] [ = ]

The next blog post will be on March 7, 2020.  Take care!

Eddie

All original content copyright, © 2011-2020.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Retro Review: Sharp EL-506A

Retro Review: Sharp EL-506A

Quick Facts:

Model:  EL-506A
Company:  Sharp
Type:  Scientific
Years:  Introduced 1985
Display:  10 digits
Batteries:  Battery, 1.5 V. 

Special thanks to Tom Manning for furnishing this calculator.  Much appreciated. 

The calculator comes in a compact folding wallet. 

Features

The available modes are:

Decimal Mode:  This is the normal scientific calculator mode. 

The EL-506A has two memory registers, M1 and M2.   There are three keys dedicated to the memory registers:  [ x→M ] (store), [ RM ] (recall), and [ M+] (storage addition).  Memory 1 is the primary key while memory 2 is the secondary key.  Contents of the memory registers are retained even when the calculator is turned off. 

Complex Mode:  Use the [ a ] and [ b ] keys for complex number arithmetic calculations.  Rectangular and Polar conversions are included in this mode ( →xy, →rθ).  Complex mode is toggled on and off by the [ 2ndF ] [ . ].

Base Conversions:  Binary, Octal, and Hexadecimal modes are toggled by the key sequences [ 2ndF ] [ ÷ ], [ 2ndF ] [ × ], and [ 2ndF ] [ - ] respectively.  When going to these modes, the number in the displayed is converted.  Boolean functions  include NOT, AND, OR, XOR, XNOR, and NEG.

3-VLE Mode:  The 3-Variable mode solves 3 x 3 systems of linear equations:

a1 * x + b1 * y + c1 * z = d1
a2 * x + b2 * y + c2 * z = d2
a3 * x + b3 * y + c3 * z = d3

The mode solves for x, y, and z, and gives the determinant of the matrix

[ [ a1, b1, c1 ]
[ a2, b2, c2 ]
[ a3, b3, c3 ] ]

The 3-VLE mode becomes a stable for advanced Sharp scientific calculators during the late 1980s and 1990s. 

The mode is toggled on and off with the [ 2ndF ] [ +/- ] sequence.

Statistics Mode:  The EL-506A has one variable statistics.  There are three functions to transform data in normal distribution calculations.

→t:  Calculates (x - μ) / σ
→t Q(t):  Calculates the area between 0 to t
→t P(t): Calculates the area between -∞ to t

The statistics mode is toggled on and off with the [ 2ndF ] [ ON/C ].  I am not a fan of this key sequence, but thankfully it works because the calculator is not solar powered. 

Keyboard

The keyboard is a clean design.  Despite the small keys, the keys are responsive and easy to operate. 

Verdict

The EL-506A is a nice vintage calculator with several advanced features like base conversions, the normal distribution functions, and 3 x 3 linear system solver. 

Source:

"Sharp EL-506A"  calculator.org
https://www.calculator.org/calculators/Sharp_EL-506A.html
Retrieved December 19, 2019

Eddie

All original content copyright, © 2011-2020.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Retro Review: Casio fx-280 FRACTION

Retro Review:  Casio fx-280 FRACTION

Quick Facts:

Model:  fx-280 FRACTION
Company:  Casio
Type:  Scientific
Years:  Introduced 1995 (mid 1990s)
Display:  10 digits
Batteries:  Solar with Battery backup, LR 44

Special thanks to Tom Manning for furnishing this calculator.  Much appreciated. 

A Bigger fx-260 Solar (II)

The Casio fx-280 FRACTION is a variation of the Casio fx-260 Solar and the fx-260 Solar II.  The modes and features are:

*  Trigonometric Functions
*  Angle Conversions:  polar, rectangular, degrees/radians/grads
*  Random Numbers
*  Logarithms and exponents
*  1 Variable Statistics
*  Fractions
*  DMS/Decimal conversions

Like the great fx-260 Solar, the fx-280 calculator is an impressive basic scientific calculator, handy for both beginners and experts.  You can check my review for the fx-260 Solar II here:  http://edspi31415.blogspot.com/2017/03/review-casio-fx-260-solar-ii-fx-82.html

Any Differences?

Yes.  The main difference is that the fx-280 has three memory registers:  A, B, and M.   Only memory M has storage addition.  Memories A, B, and M are assigned to the [ ( ], [ ) ], and [ x^y ] keys, respectively. 

The top row of keys has a [STO] (RCL)  (store/recall), pushing the [x^2] (√), [log] (10^x), and [ln] (e^x) keys to the right.  The fx-280 has no [ON] key, and the [AC] key acts as the ON key. 

The arithmetic keys, equals key, and M+/DATA key are blue instead of black.  The [ C ] and [AC] keys are red.

The fx-280 came with a quick reference card.

Thank you Tom! 

Source:

"Casio fx-280 (FRACTION)"  calculator.org  https://www.calculator.org/calculators/Casio_fx-280.html  Retrieved December 11, 2019

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

TI-74: Five Stencil Derivative, Vertical Height on a Hill, Solving Cubic Equations

TI-74:  Five Stencil Derivative, Vertical Height on a Hill, Solving Cubic Equations

TI-74 Program: Five Stencil Derivative

This program estimates the numerical derivative of f(x) at x0 by the formula:

f'(x0) ≈ ( -f(x0+2h) + 8*f(x0+h) - 8*f(x0-h) + f(x0-2h) )/(12h)

Source:  "Five Stencil Method"  Wikipedia.  Page last edited November 8, 2018.  https://en.wikipedia.org/wiki/Five-point_stencil  Retrieved April 14, 2019

Note:  comments (after !) are for notes, and do not need to be typed. 


500 PRINT "F(X) IS ON LINE 550.": PAUSE 1: RAD  ! RAD sets radians mode
502 INPU T "X: ";A
504 INPUT "H: ";H
506 D=0: X=A+2*H: GOSUB 550
508 D=-F: X =A+H: GOSUB 550
510 D=8*F+D: X=A-H: GOSUB 550
512 D=D-8*F: X=A-2*H: GOSUB 550
514 D=(D+F)/(12*H)
516 PRINT "DF/DX =";D: PAUSE 
518 END
550 F=5.2^X  ! Insert F(X) here
552 END

Examples:

550  F=5.2^X
x0 = 1.2, h = 0.001, Result:  11.92160564

550 F=EXP(X)*SIN(X)
x0 = PI/3, h = PI/24, Result: 3.892851849

TI-74 Program:  Vertical Height on a Hill

Variables:
H = height of the observer
L = horizontal length
V = vertical angle (entered in degrees-minutes-seconds, DD.MMSSSS)
G = ground slope (entered in degrees-minutes-seconds, DD.MMSSSS)

If G>0, the hill is at an elevation.  If G<), the hill is at an depression.

T = total height = vertical difference + observer's height
T = L * (tan V - tan G) + H

Since there is no DMS to decimal conversion function in TI-74's basic, a conversion is necessary. The following is sample code where A is DMS format needed to be converted:

T = ABS(A)
D = INT(T)
M = INT((T-D)*100)
S = ((T-D)*100-M)*100
A = (D+M/60+S/3600)*SGN(A)

The program code is shown below:

600 INPUT "LENGTH: ";L
602 INPUT "OBSERVER'S HEIGHT: ";H   ! ' is SHIFT + SPACE

604 DEG: PRINT "ANGELS IN DD.MMSSSS": PAUSE 1.5
606 INPUT "VERTICAL ANGLE: ";V: A=ABS(V)
608 D=INT(A): M=INT((A-D)*100): S=((A-D)*100-M)*100
612  V=(D+M/60+S/3600)*SGN(V)

614 INPUT "GROUND SLOPE: ";G: A=ABS(G)
616 D=INT(A): M=INT((A-D)*100): S=((A-D)*100-M)*100
618 G=(D+M/60+S/3600)*SGN(G)

620 T=L*(TAN(V)-TAN(G))+H
622 PRINT "TOTAL HEIGHT =";T: PAUSE
624 END

Examples:

Input:  L: 10 m, V: 30°14'33", G: 10°30'00", H = 1.7780 m
Result:  T = 5.754638129 m

Input:  L: 10 m, V: 30°14'33", G: -10°30'00", H = 1.7780 m
Result:  T = 9.461464028 m

Source: 

F.A. Shepherd "Engineering Surveying: Problems and Solutions" 2nd Edition  Edward Arnold Publishers Ltd.  London, UK  1983 ISBN 0-7131-3478-X

TI-74 Program:  Solving Cubic Equations

This program solves the cubic equation:

A*X^3 + B*X^2 + C*X + D = 0

This program uses Newton's method to get the first root, then divides the polynomial by (x - root).  Finally the quadratic formula is used to find the other two roots.  This program assumes the coefficients A, B, C, and D are real.  An initial guess of 1 is used (can be changed, see line 710).

700 PRINT "A*X^3+B*X^2+C*X+D=0, REAL COEFS.": PAUSE 1.5
702 INPUT "A: ";A
704 INPUT "B: ";B
706 INPUT "C: ";C
708 INPUT "D: ";D

710 X=1
712 XN=X-(A*X^3+B*X^2+C*X+D)/(3*A*X^2+2*B*X+C)
714 IF ABS(XN-N)<1e-9 718="" font="" then="">
716 X=XN: GOTO 712

718 X1=XN
720 PRINT "X1 =";X1: PAUSE
722 J=-(A*X1+B)
724 K=(A*X1+B)^2-4*A*(A*X1^2+B*X1+C)
726 IF K<0 750="" font="" then="">
728 X2=(J+SQR(K))/(2*A): X3=(J-SQR(K))/(2*A)
730 PRINT "X2 =";X2: PAUSE
732 PRINT "X3 =";X3: PAUSE
734 END

750 XR=J/(2*A): XI=SQR(ABS(K))/(2*A)
752 PRINT XR;"+- ";XI;"I": PAUSE
754 END

Example:
A: 1, B: 1, C: -9, D: -9
Roots: -3, 3, 1
Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

TI-74: Lottery, Solving Linear Equation Script, Escape Velocity Solver

TI-74:  Lottery, Solving Linear Equation Script, Escape Velocity Solver

TI-74 Program:  Lottery

This program collects six random digits from 1 to 63.  The results are stored in an array N.  The dimension pointers of the TI-74 are from 0 to n-1. 

To execute:  RUN 200

Note:  comments (after !) are for notes, and do not need to be typed. 

200 DIM N(5)
202 INPUT "SEED: ";S
204 RANDOMIZE S
210 FOR I=0 TO 5    ! choose random numbers
212 R=INT(RND*63+1)
220 FOR J=0 TO 5   ! check to see if the random number is unique
222 IF R=N(J) THEN 212
224 NEXT J
230 N(I) = R
232 K=K+1
234 PRINT "# "&STR$(K)$": "&STR$(N(I))
236 PAUSE 1.5
240 NEXT I
242 END

TI-74 Program:  Solving Linear Equation Script

This program uses READ and DATA to execute a teaching script.

To execute:  RUN 300

300 FOR I=1 TO 5
302 READ S$  ! string variables have the dollars sign after the name
304 PRINT S$: PAUSE
306 NEXT
310 DATA "To Solve: a*x + b = c"
312 DATA "a*x + b - b = c - b"
314 DATA "a*x = c - b"
316 DATA "(a*x)/a = (c-b)/a"
318 DATA "x = (c-b)/a"
320 END

TI-74 Program:  Escape Velocity Solver

This program is in two stages:
1.  Enter data.  Use M, R, or V to enter data.  When done, press C to solve.
2.  Choose which variable to solve for. 

M = mass of the planet in kg
R = radius of the planet in km
V = escape velocity in km/s

G = Universal Gravitational Constant
= 6.672E-11 m^3/(kg*s^2) = 6.672E-20 km^3/(kg*s^2)

Equation:  V = √(2 * G * M/R)

To execute:  RUN 400

400 M=0:R=0:V=0:G=6.674E-20
402 PRINT "M MASS, R RADIUS, V VEL, CALC":K$=KEY$
406 IF K$="M" THEN 420
408 IF K$="R" THEN 430
410 IF K$="V" THEN 440
412 IF K$ = "C" THEN 450
414 GOTO 402   ! repeats loop if any other key is pressed

420 INPUT "MASS (KG): ";M
422 GOTO 402
430 INPUT "RADIUS (KM): ";R
432 GOTO 402
440 INPUT "VELOCITY (KM/S): ";V
442 GOTO 402
450 PRINT "SOLVER: M,R,V": K$=KEY$

452 IF K$="M" THEN 460
454 IF K$="R" THEN 470
456 IF K$="V" THEN 480
458 GOTO 450

460 M=V^2*R/(2*G)
462 PRINT "MASS =";M;" KG": PAUSE
464 GOTO 490
470 R=2*G*M/V^2
472 PRINT "RADIUS =";R;" KM": PAUSE
474 GOTO 490
480 V=SQR(2*G*M/R)   ! SQR is √
482 PRINT "VELOCITY =";V;" KM/S": PAUSE
484 GOTO 490

490 PRINT "AGAIN? Y/N": K$=KEY$
492 IF K$="Y" THEN 402
494 IF K$="N" THEN END
496 GOTO 490

Examples: 

Solve for V:   M: 5.9724E24 kg, R:  6374 km,  Result: V ≈ 11.178 KM/S
*Escape Velocity for Earth

Solve for M:  R: 5800 km, V: 16 km/s,  Result:  M ≈ 1.112E25 kg

Solve for R:  M: 3.8E24 kg, V: 22 km/s, Result:  R ≈ 1048.0148 km

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.