Electrical Engineering XYZ MCQ
If lowest critical frequency is due to zero and it may be present at the origin or nearer to the origin, then the type of network will be:
- RL circuit
- LC circuit
- RLC circuit
- RC circuit
Correct answer: 1. RL circuit
Explanation: In electrical circuits, especially in the context of filters and network analysis, the concept of poles and zeros is crucial. The presence of poles and zeros in the transfer function of a network determines its behavior.
In the context of the given question, if the lowest critical frequency is due to a zero and it may be present at the origin or nearer to the origin, it implies that the reactance approaches zero at that frequency. This can occur when there’s an inductor in the circuit.
In an RL circuit, the transfer function has a pole at the origin (due to the inductor) and potentially a zero close to the origin (due to a parallel resistor or other circuit elements). When the frequency reaches the value where the zero dominates, the reactance becomes effectively zero, resulting in the lowest critical frequency.
So, considering the presence of zeros and their relation to the lowest critical frequency, the correct answer is RL circuit.