The principle of solar power generation is that solar panels receive sunlight and generate photoelectric effect on the substrate of the solar panels, thus converting light energy into electric energy;  Then the electric energy is stored through a storage battery.

The solar wireless char circuit can be designed as that circuit of fig. 4.  In fig. 4, the transistor emitter-coupled multivibrator and the analog darlington tube we selected form a wireless charging circuit. the emitter-coupled multivibrator consists of two low-power triodes. according to the component data in fig. 4, the oscillation frequency is about 350kHz.  Among the components, only the last triode VT4 has higher dissipation power, and the others are relatively simple and easily available components.

wireless charging circuit

The 12V power supply is provided by a solar charging circuit. The power supply signal is converted into a high-frequency signal through an emitter coupled multivibrator circuit and then amplified by an analog Darlington power amplifier circuit through a coupling circuit consisting of C3 and R7. L1 and L2 are primary and secondary coupling coils respectively. The amplified signal is wirelessly transmitted to a secondary receiving circuit through the coupling of L1 and L2. The high-frequency AC signal is rectified and filtered and converted into direct current to charge a 3.7V lithium battery.