In a cooler or fan, which is used in power supplies and other household appliances, there is a chip called fs276 or ats276 or ah276 or maybe even under other names, the main thing on the case is the inscription 276 or 277 (this is an approximate analogue of 276).This chip has four outputs and it contains a Hall sensor, an amplifier and a driver with two key transistors at the output, to the collectors of which the load is connected.There is a round magnet with poles in the cooler blades.The Hall sensor reacts to these poles of the magnet and switches the coils, thereby rotating the fan blades.
The Hall sensor is located in the front part of the chip.
Characteristics of the chip: operating voltage from 2.8 to 20 Volts and current consumption up to 450 mA.
Several simple and interesting electronic devices can be assembled on this chip.
The first device is a tachometer, which will help to measure the engine speed.We put a magnet on the motor shaft and bring the chip to the rotating motor shaft.There will be a signal at the output of the chip that will show the rotation frequency in Hertz.This signal can be applied to the microcontroller or just look at the oscilloscope screen.The frequency in Hertz is multiplied by 60 and we get the number of revolutions per minute.In the photo, the frequency is 38 Hz, so the revolutions are about 2280 per minute.
With the help of the second device, the poles of the magnet can be determined.When power is applied, one of the LEDs shines.We bring a round magnet from the speaker to the chip and the LEDs switch.
The third homemade is a brushless motor.I took the cylinder magnet from the phone’s vibration ring, although not every vibration ring has such a magnet.I inserted a drill bit into this magnet and wound two coils of 200 turns each.I installed the chip so that when the power is applied, the magnet starts to rotate quickly.
