Advanced Qualification · A-001 Advanced theory · A-001-001-001
What is the meaning of the term "time constant" in an RL circuit ?
- AThe time required for the voltage in the circuit to build up to 63.2% of the maximum value
- BThe time required for the voltage in the circuit to build up to 36.8% of the maximum value
- CThe time required for the current in the circuit to build up to 63.2% of the maximum value
- DThe time required for the current in the circuit to build up to 36.8% of the maximum value
Correct answer: C — The time required for the current in the circuit to build up to 63.2% of the maximum value. From the official ISED question bank, verified word for word.
Why
In an RL circuit, which contains a resistor and an inductor, the current does not jump instantly to its full strength when power is applied. The full explanation — and one for every question — is in Pro.
Practise this section
Advanced theory is section A-001 of the Advanced exam: Advanced theory: time constants, reactance, impedance, resonance, Q, and the mathematics behind tuned circuits.
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