Transient Response
Transient Response
- Study the transient response of a series RC circuit.
- Understand the time constant concept by using fluctuating signal.
Transients = circuit responses to sudden changes in a circuit.
- The transients in the system occur because of presence of energy storage elements like inductor and capacitor
- The energy stored in such elements (L and C) cannot change instantaneously and will oppose the sudden change in system which results in instability due to oscillation.
- Inductor opposes sudden change in current
- Capacitor opposes sudden change in voltage
Behavior of inductor in transient:
When we try to increase current in an inductor suddenly, (i.e. $\dfrac{di}{dt} = \infty$), voltage developed across it will be infty as $V_L = L\dfrac{di}{dt} = \infty$ i.e. inductor acts as open circuit (i-0 as V= $\infty$) Thus the action of sudden in current is counteracted by establishing open circuit.
Behavior of capacitor in transient:
When we try to increase voltage in a capacitor suddenly, (i.e. $\dfrac{dv}{dt} = \infty$), current developed across it will be infty as $I_C = C\dfrac{dv}{dt} = \infty$ i.e. capacitor acts as short circuit (v = 0 as i= $\infty$) Thus the action of sudden in voltage is counteracted by establishing short circuit.
Terminology:- Just before switching (from t = $\infty$ to t = 0$^-$)
- Just after switching (At t = 0$^+$)
- After switching: (For t >0)
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