Capacitors in parallel:

Three capacitors are connected in parallel. If on closing the switch S a current I flows in the circuit, then from Kirchoff's first law:

I  =  I₁  +  I₂  +  I₃

          therefore   It  =  I₁t  +  I₂t  +  I₃t   (where 't' is the time)

          but             Q  =  It

          therefore   Q_TOTAL   =  Q₁  +  Q₂  +  Q₃

          therefore          

          but             Q/V  =  C

          Therefore  C  =  C₁  +  C₂  +  C₃

Thus, we may replace capacitors in parallel by a single capacitor whose value is given by the above equation.