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

In summary, when a lc resonant tank circuit is disconnected from power, the length of time it will oscillate can be determined by calculating the time constant, which is 2Q/frequency. Q, the quality factor of the circuit, can be calculated from the given values of L, C, and the resistance of 500 ohms. The amplitude of oscillations will decrease exponentially and will never reach zero.
  • #1
hobbs125
108
0
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
 
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  • #2
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.
 
  • #3
Ok, so how would I calculate that?
 
  • #4
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)
 
  • #5
Awesome, thank you.
 

1. How does a lc tank circuit work?

A lc tank circuit is a type of electric circuit that consists of an inductor (L) and a capacitor (C) connected in parallel. When power is applied, the capacitor charges up and stores energy. As the capacitor discharges, it transfers the energy to the inductor, which in turn creates a magnetic field. This cycle repeats, resulting in an oscillating current.

2. What is the purpose of a lc tank circuit?

A lc tank circuit is commonly used in radio and television receivers, as well as in electronic oscillators. Its main purpose is to generate and maintain a stable oscillation at a specific frequency, which can be used for tuning or transmitting signals.

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

The duration of oscillation in a lc tank circuit depends on several factors, such as the values of the inductor and capacitor, as well as the resistance in the circuit. Generally, the oscillation will continue until all the energy stored in the circuit is dissipated through resistance, which could take a few milliseconds to several seconds.

4. Can the oscillation in a lc tank circuit be controlled?

Yes, the oscillation in a lc tank circuit can be controlled by adjusting the values of the inductor and capacitor. By changing the capacitance or inductance, the resonant frequency of the circuit can be altered, leading to a change in the oscillation period.

5. What factors can affect the oscillation in a lc tank circuit?

Apart from the values of the inductor and capacitor, the resistance in the circuit can also affect the oscillation in a lc tank circuit. Higher resistance can lead to a quicker dissipation of energy and result in a shorter oscillation period. Additionally, external factors such as temperature and interference can also impact the oscillation in a lc tank circuit.

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