A slip ring assembly that uses sliding contact to transmit low frequency signals and energy. There are two common slip rings: cylindrical slip ring and differential slip ring. The conductive ring of cylindrical slip ring is divided into flat ring and V ring. Conductive rings are usually made of copper, brass, coin silver and gold. There are palladium, gold alloy or gold plated wire brush and copper graphite composite brush. If the number of slip rings is large, the cylindrical slip ring consists of two sets of upper and lower brushes and a differential transfer plate, but its axial size is large, and the use of differential slip rings can significantly reduce the axial size, volume and weight. The differential slip ring consists of an upper and a lower set of brushes and a differential transfer plate. The upper brush rotates with the azimuth of the antenna, and the lower brush is fixed. There are two groups of contact sheets on the differential transfer plate. The corresponding contact sheet is connected by a wire and the speed of the differential mechanism is 1/2 of the azimuth speed. When the antenna is rotating, the current flowing into each brush flows out of the corresponding upper brush through one or two contact plate circuits on the differential turntable to ensure that the circuit between the fixed part and the rotating part is always connected. The powder worn by the sliding contact slip ring may cause a short circuit between the rings. Therefore, it should be structurally easy to clean up, usually with a modular structure for on-site repair or replacement of components.