In AC circuits containing capacitors, inductors, and resistors withseries resonance, forced electrical resonance of current and voltage occurs. At a certain frequency of alternating current, inductance and capacitance resistance may be equal (Xt=Xc). This means that the current intensity and applied voltage vary in the same phase, as if there were only Ohmic resistors in a circuit, and the voltage amplitudes on inductors and capacitors are the same but opposite in phase. This phenomenon is calledseries resonance or variable frequency resonance. The resonant frequency is determined by the formula

The series resonance phenomenon is used in radio engineering to tune circuits to the desired frequency.

When the frequency approaches the resonant frequency C0res [t] when a voltage is applied, there is a sharp decrease in the amplitude of the current intensity in an AC circuit powered by parallel connected capacitors and inductors (ignoring the active resistance due to its small size). Eco ->so1=Vl ((LC)], known as parallel resonance. The branch circuit of capacitors and inductors has a high impedance to AC power, and the frequency of AC power is close to the resonant frequency. The characteristic of parallel resonance has been applied in resonant amplifiers, which enable isolation of a specific oscillation from complex shaped signals, as well as in induction furnaces.

AC generator - a device that generates current by converting any energy

Both are converted into electrical energy. For example, in an induction generator, the phenomenon of electromagnetic induction is used to convert mechanical energy into electrical energy. The simplest model of a generator is a wireframe rotating in a uniform magnetic field. In this case, the magnetic flux penetrating the frame changes according to the law of Φ=BScoswf, where B is the magnetic induction module and S is the area of the frame.

There is a variable induced electromotive force in the framework:

Among them, r max=BSco is the maximum value of induced electromotive force.

The rotating part of the generator is called the rotor, and the stationary part is called the stator.

If current passes through a frame placed in a magnetic field, the frame will begin to rotate. The operation of electric motors designed to convert electrical energy into mechanical energy is based on this principle.