function calcohm(form,val,index)
// calculations for electrical resistance, conductance, June 2003
// version 2: September 2004
// copyright Bernd C. Krueger 2004-2006
{
    var sto_o=8.9875518e11;            // statohm per ohm
    var value=parseFloat(val);
    if(value<=0){warnings(1);return;}

    if(index==-1) { v=form.storev.value; if(v==0) return; }
    if(index==0) v=value;         // ohm (base)
    if(index==1) v=value*1.0e3;   // kohm
    if(index==2) v=value*1.0e6;   // Mohm
    if(index==3) v=value*1.0e-9;  // abohm
    if(index==4) v=value*sto_o;   // statohm
    if(index==5) v=1./value;      // S
    if(index==6) v=1.0e3/value;   // mS
    if(index==7) v=1.0e6/value;   // muS
    if(index==8) v=1.0e-9/value;  // abmho
    if(index==9) v=sto_o/value;   // statmho
    form.storev.value=v;

    form.ohm.value = ausga(form,v);         // ohm (base)
    form.kohm.value = ausga(form,v/1.0e3);  // kohm
    form.mohm.value = ausga(form,v/1.0e6);  // Mohm
    form.aohm.value = ausga(form,v/1.0e-9); // abohm
    form.sohm.value = ausga(form,v/sto_o);  // statohm
    form.sie.value  = ausga(form,1.0/v);    // S
    form.msie.value = ausga(form,1.0e3/v);  // mS
    form.ysie.value = ausga(form,1.0e6/v);  // muS
    form.asie.value = ausga(form,1.0e-9/v); // abmho
    form.ssie.value = ausga(form,sto_o/v);  // statmho
    return;
}