Scientific Calculator

jimofadel/Jim3

By jimofadelay

EE functions

Tagged: capacitor divider parallel reactance regulator resistor

//Rstd(r) returns the closest standard resistor value to given  r
//uses standard 1% (E96) values, but limited to 24 values per decade (10% intervals)
Rstd=function(r) {
   r < 1 ?
       (
        error("not valid for r < 1");
       ):(r=r);
n=range(0,25);
Rval=10^(n/24);
m=1;
while (m < 27) -> (
    rx=round(Rval[m]*100)/100; //round to 3 sig. digits
    Rval[m]=rx;
    m=m+1;
  );     
   dec=ipart(log10(r));
   Rvals=Rval*10^dec;
   D = Rvals-r;
   done=0;
   xover=[0,0];
   Rs=Rvals(1);
   j = 1;
   err="done";
   while (( j < 24.5) and (done==0) ) -> (
            (abs(D(1)) < .05*r)and(j=1) ?
                 (
                  Rs = Rvals(j);
                  done = 1;
                  ):
                  (done = 0;
                   );
            D(j+1) > 0 ?
                 (
                  xover=[j,j+1];
                  abs(D(j)) < abs(D(j+1)) ?
                        (
                         done=1;
                         Rs=Rvals(j);
                         ) :
                        (
                        Rs=Rvals(j+1);
                        done=1;
                         ) ;
                  ) :
                  (
                  done=0;
                   ) ;
                   j=j+1;        
        ); // end while 
       
   output=[Rs];
   output;
   }; //end function


//vout returns the output voltage of a regulator given divider resistors and reference
vout=function(Rtop,Rbot,Vref) {
    Vref+Rtop*(Vref/Rbot);
};
//Xc returns capacitive reactance given  capacitance and frequency
Xc=function(c,f) {
    1/(2*pi*f*c);
};
//Xl returns inductive reactance given inductance and frequency
Xl=function(l,f) {
    2*pi*f*l;
};
//Cx returns capacitance required for given reactance and frequency
Cx=function(x,f) {
    1/(2*pi*f*x);
};
//Lx returns inductance required for given reactance and frequency
Lx=function(x,f) {
    x/(2*pi*f);
};
//divr returns ratio provided by given resistors of a simple divider
divr = function(Rtop,Rbot) {
     Rbot/(Rbot+Rtop);
};
//par returns the resistance of a and b in parallel
par = function(a,b) {
    a*b/(a+b);
};
//diss returns dissipation of a regulator with given output power and efficiency
diss=function(pout,eff) {
    (pout/eff - pout);
};

//Cstd returns closest standard capacitor value to given c
Cstd=function(c) {
c<1 ? (c=c):(error("C must be < 1"));
Cval=[1,1.2,1.5,1.8,2.2,2.7,3.3,3.9,4.7,5.6,6.8,8.2,10];
   dec=ipart(log10(c))-1; //c < 1
   Cvals=Cval*10^dec;
   D = Cvals-c;
   done=0;
   xover=[0,0];
   Cs=Cvals(1);
   j = 1;
   err="done";
   while (( j < 13.5) and (done==0) ) -> (
            (abs(D(1)) < .05*c)and(j=1) ?
                 (
                  Cs = Cvals(j);
                  done = 1;
                  ):
                  (done = 0;
                   );
            D(j+1) > 0 ?
                 (
                  xover=[j,j+1];
                  abs(D(j)) < abs(D(j+1)) ?
                        (
                         done=1;
                         Cs=Cvals(j);
                         ) :
                        (
                        Cs=Cvals(j+1);
                        done=1;
                         ) ;
                  ) :
                  (
                  done=0;
                   ) ;
                   j=j+1;        
        ); // end while 
       
   output=[Cs];
   output;
   }; //end function

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