Download Fluid flow analogy

Fluid flow analogy
Power and energy in an inductor
Capacitor v-i equation
Capacitor Power equation
Capacitor : power and energy
Capacitor : power and energy
The self- and mutually induced voltages
The self- and mutually induced voltages
7-1 . The natural response of an RL circuit
• Independent current source IS .
• The switch has been closed for a “long time”.
• L di/dt = 0 at t <0 (before the release of stored energy) ;
the inductor appears a s a short circuit .
• No current in R0 and R ; all the current appears in L
branch .Finding v(t) and i(t) for t>=0 .
Expressions for the current
LR Circuits
Equations
RL circuits (cont’d)
RL circuits (cont’d)
RL circuits (cont’d)
Time constant
Time constant
(1% of the initial value at five time constants)
-less than 5 constants : the transient response
- exceeds 5 constants : steady- state response
Time constant (cont’d)
Equations (cont’d)
Determination of time
constant
Calculating the response of RL circuit
7-2 The natural response of an RC circuit
• An RC circuit is analogous to an RL circuit
• The switch has been in the position for a long time such
that all the elements in the circuit reach a steady-state
condition .
• A source voltage exists between the terminals.
• Circuit after switching is shown in Fig. 7-11 .
Expression for the voltage
Circuit consisting of R,
C and Vg