The discharge equation:
V(t)=V0e−t/T,where
T=RC is a time constant. The total charge in the first 5 time constants thus is:
Q=C⋅V(5T)=C⋅V0e−5==1.5⋅10−3⋅24⋅e−5=2.43⋅10−4 C.Now predict how long it would take to discharge our capacitor to 0.03 coulombs (when the voltage of course will be
V=Q/C=0.03/(1.5⋅10−3)=20 V). Express
t from the first formula:
t=−RC⋅lnV0V=−0.15⋅ln2420=0.027 s
Comments
Leave a comment