Flash Code for Decibel Computation

 

 

 
 

         

Shown below is a 'running' Macromedia Flash program for computing the decibel equivalent of the ratio between two values of power or two values of voltage. Likewise shown below the program window is the Flash code used for the application, for reference by students learning to program in Flash in the context of electronics engineering.

   

 

The ratio between two values of power, P2 and P1, may be expressed in decibels according to the following formula:  dB = 10 log P2/P1.  To try the program, choose 'Power' from the listbox, input 100 for P2 (for 100 watts) and 1 for P1 (for 1 watt), and then press compute. The output will display 20 (for 20 decibels), which means that a power ratio or gain of 100 may be expressed as 20 dB. 

   

Also, since P=V2/R, then dB = 10 log (V2/V1)2 = 20 log V2/V1. To try this with the program, choose 'Voltage' from the listbox, input 100 for V2 (for 100 V) and 1 for V1 (for 1 V), and then press compute. The output will display 40 (for 40 decibels), which means that a voltage ratio or gain of 100 may be expressed as 40 dB. 

 

         
         

mx.accessibility.ButtonAccImpl.enableAccessibility();
  
function Compute(){
     var Inp1:Number = parseFloat(txtInp1.text);
     var Inp2:Number = parseFloat(txtInp2.text);
     switch (cmbCompute.text){
          case "Voltage" :
               txtDb.text = 20 * (Math.log(( Inp2 / Inp1 ))* Math.LOG10E) ;
               break;
          case "Power" :
               txtDb.text = 10 * (Math.log(( Inp2 / Inp1 ))* Math.LOG10E) ;
               break;}
}
   
cmdCompute.addEventListener("click",Compute);