We know the Magnet has two Polarity called North pole and South pole, if each poles attracts each other definitely one is North and another one is South pole, if each other repels each then these two are same pole.
But here we can’t decide which is South and North pole, to make the task easy the following circuit helps you lot.
Magnet Polarity Detector Circuit Diagram
This circuit constructed by using few easily available components, main part of this circuit is APX9141 Hall Effect sensor. It has Hall element and two different outputs as DO and DOB by using these output we can easily detect poles of Magnet.
Here the Red LED connected in DO (pin 2) it represents North pole, and Blue LED connected in DOB (pin 3) it represents South pole.
This sensor can operates in 3V hence the CR2032 3V Cell is placed to provide bias.
Hall Effect Sensor IC with Reverse Voltage Protection from ANPEC.
• On-chip Reverse Voltage Protection
• On-chip Hall Sensor
• Low Operating Supply Voltage : 3 V
• High Output Sinking Capability up to 400mA
• Versatile sensitivity and hysteresis setting
• Reliable and Rugged
• 4 pin TO-92M Package