The earliest encoders on the market were mainly rotary transformers.

A transformer is an electromagnetic sensor, also known as a synchronous decomposer. It is a small AC motor used for measuring viewpoint, used to measure the angular displacement and angular velocity of a rotating object on a star, consisting of a stator and a rotor. The stator winding serves as the primary side of the transformer and receives excitation voltage, with excitation frequencies typically ranging from 400, 3000, and 5000Hz. The rotor winding, as the secondary side of the transformer, receives induced voltage through electromagnetic coupling.

Rotating transformers can operate under some harsh environmental conditions due to their sensitivity to electromagnetic interference and chaotic decoding, which are confirmed to be used for deceleration. However, to this day, they still have their unique value, such as being irreplaceable as a speed response for hybrid vehicles.

The most commonly used brand in the market for rotary transformers is the Tamagawa rotary transformer.

Incremental encoders are currently the most widely used in the market and can be used to measure viewpoint, displacement, and speed.

An incremental encoder converts displacement into a periodic electrical signal, which is then converted into a counting pulse. The number of pulses is used to represent the magnitude of displacement. The output methods of incremental encoders include collector output, voltage output, line driven output (differential output), and complementary output (push-pull output).

The shaft type is divided into solid shaft and hollow shaft to meet the different needs of customers in different occasions.

There are many brands of incremental encoders, mainly used in the automation control of production lines such as printing machinery, shoe machines, ceramic machinery, glass machinery, inkjet printers, injection molding machinery, elevators, CNC machine tools, computer embroidery machines, embroidery machines, textile machinery, packaging machinery, cardboard machinery, oiling machines, automation equipment, cutting machinery, and large-scale knitting machinery.

Incremental encoders are commonly used in the market, such as Beverly, Omron, Beijiafu, Sike, Turck, and so on.

The usage of absolute value encoders in the market is not small now, and the price of absolute value encoders is relatively high compared to incremental star encoders, mainly used for measuring displacement.

Each position of the absolute encoder corresponds to a confirmed numerical code, so its indication is only related to the starting and stopping positions of the measurement, and is not related to the central process of the measurement.

Absolute encoder printing machinery, shoe machines, ceramic machinery, glass machinery, inkjet printers, injection molding machinery, elevators, CNC machine tools, computerized embroidery machines, embroidery machines, textile machinery, packaging machinery, cardboard machinery, oiling machines, automation equipment, cutting machinery, large-scale knitting machinery and other production line automation control categories.