"220V Cooling Fan" control core microcontroller. Designed to focus on the practical application of the MCU. AT89C51 microcontroller chip 51 of the most commonly used. In the system design, we can use AT89C51 microcontroller as the controller. AT89C51 is a 4K byte with the low voltage flash erasable programmable read-only memory, "220V Cooling Fan" high performance CMOS8 bit microprocessor. The device uses ATMEL high density non-volatile memory manufacturing technology manufacturing, is compatible with the industry-standard MCS-51 instruction set and output pins. Since the multi-purpose 8-bit CPU and flash memory combined in a "220V Cooling Fan" single chip, ATMEL's microcontroller AT89C51 is a highly effective for many embedded control system provides a high flexibility and low cost of the program .