• +1-818-527-9935
  • Register

Postby TGTS0907129» Concept of electric oscillations

Describe the concept of electric oscillations


In the study of mechanical vibration it was found that oscillations can be set up in a body if certain conditions are present. The body must if certain conditions are present. The body must have inertia, a distortion must produce a restoring force, and the friction must not be too great. A massive objective suspended in air by a spring meets these conductions.
In an electric circuit, analogous conditions are necessary for electric oscillation. Just as inertia opposes charge in mechanical motion, inductance opposes change in the flow of electrons. The blinding up of charge on the plates of a capacitor cases a restoring force on the electrons in the circuit. Resistance causes electric energy to be changed into heat, just as friction changes mechanical energy to heat. To produce electric oscillations, it is necessary to have inductance, capacitance, and not too much resistance. As the frequency of mechanical vibrations depends upon the inertia (mass) and restoring force (force constant), so the frequency of electric oscillations depends upon inductance and capacitance.

In the circuit capacitor of capacitance C and a coil of inductance L are connected in series with a sphere gap G. The sphere gap has a high resistance until a spark jumps across but low resistance after the spark jumps. If the voltage across G is gradually increased, the charger on the capacitor will increase. When the voltage across G becomes high enough, a spark will jump and the capacitor wills then discharge. The current does not ceases at zero when the capacitor is completely discharged but continues, charging the capacitor in the opposite direction. It then discharged again, the current reversing in the circuit. The current oscillates until all the energy stored in the capacitor has been converted into heat by the resistance is high all the energy is used in the first surge and hence there are no oscillations.

The frequency  f of the oscillation is determined by the values of L and C and is the frequency for which the impedance of the circuit is the least, i.e., the frequency for which the net reactance is zero. Where L is the inductance is henry and C is the capacitance in farads.

By TGTT06081269 on 9/18/2015 4:51:51 AM
TGTS0907129 on 9/18/2015 4:50:42 AM

Return to Forum