1.1. Energy. 1.2. Entropy. 1.3. The law of marginal utility of investment cycle. 1.4. The law of normal distribution. 1.5. Radioactive disintegration. 1.6. Transmission of power. 1.7. Complex numbers. 1.8. Connection between exponential function and trigonometric functions.1.9. Electric discharge of inductor.1.10. Electric discharge of capacitor.1.11. Smooth charging of capacitor.1.12. Step-by-step charging of capacitor. 1.13. Harmonic oscillations.1.14. Energy of harmonic oscillation.1.15. Composition of harmonic oscillations. 1.16. Linear oscillations. 1.17. Resonance oscillations. 1.18. Coupled oscillations. 1.19. Parametric oscillations. 1.20. Stability of parametric oscillation system. 1.21. Oscillating circuit. 1.22. Damped oscillations into oscillating circuit. 1.23. Wave processes. 1.24. D'Alembert's equation. 1.25. Harmonic oscillation critical parameters. 1.26. Critical parameters of simple wave in local economic system. 1.27. Nonlinear wave critical parameters. 1.28. Natural power amplifiers. 1.29. Power amplifiers in local economic system. 1.30. Power amplifier stage. 1.31.Undamped oscillations in oscillating circuit. 1.32. Power gain factor and efficiency factor. 1.33. Oscillating circuit effect for power amplifier activity. 1.34. Conservative condition of oscillating circuit . 1.35. Regenerative amplifier. 1.36. Self-oscillating systems. 1.37. Oscillation excitation. 1.38. Hard mode of excitation. 1.39. Amplification ability in local economic system. 1.40. Negative resistance amplifiers. 1.41. Onset of oscillations into amplifier.1.42. Self-oscillatory stability. 1.43. Critical parameters of hard mode of excitation. 1.44. Control channels of local economic system. 1.45. Parametric pumping process. 1.46. Parametric amplifier. 1.47. Parametric converter. 1.48. Energy distribution in frequency spectrum.