How long will a lc tank circuit oscillate after power is removed?

[hobbs125]

If a lc resonant tank circuit is disconnected from power how do you determine the length of time it will oscillate.

L=1 henry, 500 ohms
C=50pf
Fres=22,507 hz

 

[KingNothing]

It will decay exponentially. Usually you specify the time it takes to reach a certain ratio of the maximum (usually 1/e or about 36%), since mathematically the amplitude of oscillations will never reach zero.

 

[hobbs125]

Ok, so how would I calculate that?

 

[f95toli]

The time constant is 2Q/frequency; where Q is the quality factor of the circuit.
In order to calculate Q you need to know the losses in the circuit; if the above values are for an ideal circuit (meaning the 500 ohms are the only dissipate losses in the circuit) them you can calculate Q from them (google Q factor)

 

[hobbs125]

Awesome, thank you.