ECALC is an RPN calculator with an emphasis on the sort of display and calculations required by an audio electronics engineer. The program is written in Basic using DrWimp and is a translation of one originally written in Tcl/Tk for Linux/Unix. The structure simple enough that it could easily be modified or extended. As supplied it runs under BASIC64 (see the !Run file). It will run unmodified under ordinary BASIC The RPN style calculator is greatly superior to the algebraic type for pretty well any calculation that can realistically be carried out without programming. It does, however, require that the user has at least some understanding of how algebraic formulae and numbers work which is probably why the algebraic type is dominant. The program has no on-screen 'keyboard' but instead is controlled directly from the computer keyboard when the entry field in the display window has focus. The window includes a display of the first five levels of the stack, which has a fixed depth of 100. The stack is never empty but is filled with zeros beyond the used levels. Error recovery is possible with undo and last x. Angles may be in degrees or radians; toggle deg/rad by select clicking on the word at the top left corner of the window. All functions are entered as character strings, the most common ones being single characters. This, and the ability to enter several operations at once, makes the calculator really easy to use. Only real numbers are handled and all calculations are carried out using double precision floating point (BASIC64). Numbers may be entered as 3300 3.3e3 3k3 and are case sensitive e.g. 2m2 = 2.2e-3 2M2 = 2.2e6 Numbers may also be entered in any of the conventional mathematical forms. Numbers are always displayed in engineering format, i.e. mantissa and exponent with the exponent always a multiple of 3. Normally the exponent is removed and the decimal point replaced by the appropriate letter (see 'math' and 'elec'). --------------------------------- Examples A series of numbers and operations may be entered at once, separated by spaces or commas. Any action is carried out when return <ret> is pressed. e.g. resistors in parallel: 22k 150k pp <ret> > 19k19 -150k pp <ret> > 22k00 noise voltage in a 15k resistor, 20kHz bandwidth (default): 15k vn rb x <ret> > 2u222 dbu <ret> > -110.8 num^2 by multiplication: 125 # x <ret> > 15k62 sqr <ret> > 125.0 three resistors in parallel, longhand: 1/(1/a+1/b+1/c) 22k r 33k r 150k r a a r <ret> > 12k13 three resistors in parallel using the pp function 22k 33k pp 150k pp <ret> > 12k13 db loss in a potential divider, 100k to source 2k2 to ground 100k 2k2 pd db <ret> > -33.34 3dB frequency of 2k2 and 15uF 2k2 15u cf <ret> > 4.823 What resistor will achieve the same cut off frequency with 10nF 4.823 10n cf <ret> > 3M300 In any of the examples, spaces may be replaced by returns, making intermediate results available. These results may be saved on the stack using # <ret> or in the memory using ms <ret> or a right click on any of the displayed stack registers. ---------------------------------- The menu operation 'save' saves the calculator state; 'recall' retrieves the previously saved state. Key Words: nA, na to nG#, nAb frequency from note (A 440) # , ' duplicate 2# , 2' dup x & y 2] swap z & y ] swap x & y [ drop 2x 2X 2d 0.5X a , + add abs absolute acos acos asin asin atan atan al2 antilog 2^x all antilog 10^x bw set bandwidth for rb cf R, C and frequency calculation clear ccc clear stack and last x cos cosine ct cents from frequency ratio d , / divide db dB from voltage ratio dbu dBu from voltage dbw dB from power ratio elec electrical format (e.g. 3k3) exp exponent e^x figs set displayed significant figures mmi convert mm to inches ( x * (1.0/25.4) ) l2 log2 ll log_10 ln log_e lra rms add voltage dBs lx push last x math math format (e.g. 3.3e3) imm convert inches to mm ( x * 25.4 ) mr recall (push) memory ms transfer x to memory (a right click on any stack register also copies it to memory) n negate nn nearest note with deviation in cents pushed on stack O X 2 (octave up) o X 1/2 (octave down) pi push pi pow , ^ y^x pd potential divider, y to input x to ground pp resistors x & y in parallel pv convert x to nearest preferred value qq , QQ quit r reciprocal ra root of sum of squares (RMS add) rb push sqare root of bandwidth rn resistor producing x voltage noise in 1 Hz bandwidth rnb resistor producing x voltage noise in the set bandwidth rs root of difference of squares (RMS subtract) s , - subtract sin sine sq square sqr square root tan tangent undo undo last operation vn noise voltage of resistor x in 1 Hz bandwidth vnb noise voltage of resistor x in the set bandwidth x , * multiply xct frequency ratio from cents xdb voltage ratio from db xdbu voltage from dbu xdbw power ratio from db

Ecalc is free software released under the GNU General Public License;

see the file 'COPYING' within the application.

The DrWimp library on which it depends for access

to the RISCOS Wimp functions can be obtained here.

Download The application with full source.

Download The application with full source, linked

with the necessary parts of the DrWimp library.