Task id12069

The alternating current circuit (Fig. 12.17) consists of ideal coils with inductance l1 = 10 mH, l2 = 20 mH, a resistor with a resistance of R = 100 kOhm and capacitors with a capacity C1 = 10 nF, C2 = 5 nF. In a closed circuit, the amplitude of the alternating current remains constant when the frequency of the sinusoidal voltage generator (constant amplitude current generator) changes. The circuit opens. It is known that at time e0 after opening the circuit, the current strengths in coils l1 and l2 have the values: i01 = 0.1 A and i02 = 0.2 A (Figure 12.17 shows the directions of the currents), and the voltage on capacitor C1 is equal to U0 = 40 V. Determine: 1. The ratio of the frequency vmax, at which the active power Рmax allocated in a closed circuit is maximum, to the frequency difference dv=v+ - v-, where v and v are the frequencies at which the active power is equal to half the maximum power Pmax. 2. The frequency of free electromagnetic oscillations in value l1C1C2l2 after opening. 3. Current strength in the AB circuit section. 4. Amplitude of current fluctuations in coil l1. Note. Neglect the mutual induction of coils l1 and l2.