Electronics - Inductors - Discussion

5*RC is the time constant required the capacitor to fully charge.

Please someone explain why we are not using 5*RC?

It must be 25 micro sec, because the current to be maximum it must take 5T.

So L/R = 5us then multiply with 5. The answer will be 25 micro sec.

What happened to 5Tc before max current achieved?

Since the circuit given is an energized RL circuit and max. current flows in that particular circuit.

And that max. current flow time depends on the circuit elements such as Resistor and Inductor.

Therefore according to network theory the time constant is given by, T=L/R.

Time constants in electrical circuits
In an RL circuit composed of a single resistor and inductor, the time constant Ï„ (in seconds) is

where R is the resistance (in ohms) and L is the inductance (in henries).
Similarly, in an RC circuit composed of a single resistor and capacitor, the time constant Ï„ (in seconds) is:

where R is the resistance (in ohms) and C is the capacitance (in farads).

[from wiki]

Please explain again.

Time constant = L/R = 5 mH/1 KOhm = 5 us