What is it?
A Hall Effect transistor is a transducer that response to a magnetic field. There three
different types of Hall Effect transistors. Each of these transistors have different
responds to the magnetic field.
What does it do?
The first transistor is a proximity switch. When a magnetic field gets close enough to
the sensor, it switches on, then off when removing it.
The second Hall Effect transistor is a latch. It reacts by switching on with one pole
then holding this state until you switch it off with the other pole. So If the north pole
of a magnet turned it on, the south pole of a magnet is then needed to turn it off.
The third hall effect transistor is a proximity sensor. When a magnet approaches the
face of the transistor, the output voltage will increase or decrease, depending on
which side of the magnet you are using.
How does it work?
The hall effect transistor requires four connections two to provide current through
the device and two to provide the output voltage.
However the negative current supply line and the negative output line are internally
Thus it becomes a three terminal device that looks similar to a transistor.
It is used in measurement of velocity, rpm, sorting, limit sensing and non-contact