A DC voltage source excites an RLC circuit as shown below. At time , the inductor and capacitor are de-energized. How much energy is dissipated in the resistor from to ?
Details and Assumptions:
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F u n P r o b l e m . I will be very happy if you continue this series.
The basic equations are V s − I R − L d T d I − c q = 0
After substituting values 1 0 − 4 I − d T d I − q = 0
As we know I = d T d q = q ˙ After substituting this 1 0 − 0 . 2 5 q ˙ − q ¨ − q = 0 Solving this double differential equation leads to q ( t ) = c 1 e − 0 . 1 2 5 t s i n ( 0 . 9 9 2 1 5 7 t ) + c 2 e − 0 . 1 2 5 t c o s ( 0 . 9 9 2 1 5 7 ) + 1 0 where c 1 and c 2 are arbitrary constant.
Using this q ( 0 ) = 0 q ˙ ( 0 ) = 0 we can find the value of c 1 and c 2 easily.
After that we will reach q ( t ) = − 1 . 2 5 9 8 8 1 2 5 e − 0 . 1 2 5 t s i n ( 0 . 9 9 2 1 5 7 t ) − 1 0 e − 0 . 1 2 5 t c o s ( 0 . 9 9 2 1 5 7 ) + 1 0 Differentiate q ( t ) to get I ( t ) I ( t ) = 1 0 . 0 7 9 1 e − 0 . 1 2 5 t s i n ( 0 . 9 9 2 1 5 7 t ) Heat dissipated H = ∫ 0 ∞ ( I ( t ) ) 2 R d t H = 5 0 . 0 0 0 5