AK8778B Sensors, Transducers

Magnetic sensors are a class of sensors that detect and respond to magnetic fields. Magnetic switches (also known as Solid State switches) are an important type used for various purposes such as monitoring the position of moving parts, measuring the speed of rotating components, and detecting the presence of metal objects. The AK8778B is a magnetic sensor and switch designed for applications in industrial, automotive, medical, and consumer markets.

The AK8778B magnetic sensor is a simple, robust switch actuated by a magnetic field. The sensing element is a two-pole reed switch, which is a simple electrical switch activated by a magnetic field and typically composed of a pair of ferromagnetic blades, called reeds, each with a contact at its end. The contacts remain open until the magnetic field is strong enough to shift the reeds together. When the magnetic field is removed, the reeds move apart, opening the contacts.

The AK8778B is an 180 degree angle, latching, non-polarized reed switch in the industry standard TO-92 package. It is supplied in a 3-pin package and requires a 2D-3D Hall effect sensor to activate the switch. The sensor is available with an adjustable "trip point” sensitivity, allowing the user to adjust the trip point to their application. It uses an external magnet and an internal coil to create a sensing zone of up to 4 cm, allowing the switch to detect ferrous objects, as well as ferromagnetic and non-ferromagnetic materials of a few millimeters in size.

The AK8778B has a wide range of high reliability applications, including positioning, speed measuring, power transmission, door security and automation, automotive applications, and consumer products. In automotive applications, the AK8778B can be used for triggering airbags, monitoring door locks, and sensing the presence of a seatbelt. In the industrial arena, its uses include controlling access points such as doors and windows, monitoring level switches, motor speed sensing, and liquid level sensing.

The AK8778B is easy to install and maintain. Its low power consumption and long duty cycle make it an ideal choice for applications with low power, such as solar-powered applications. It is also designed with a wide operating temperature range of -40°C to +65°C. The magnetic switch is provided with three leads, and can be fitted in a standard TO-92 package with a hole for mounting.

The AK8778B works in three main stages: detecting the presence of a magnetic field, switching the output, and holding the output in the switched or reset position. The sensor has two separate internal magnets, each positioned at 180° angles to each other. When a magnetic field is detected, the two internal magnets pull the reed switch blades together, triggering the switch. The switch then switches the output of the sensor, which can be used to trigger other circuits, such as to turn on lights or control power to certain devices or machines. Once the magnetic field is removed, the switch returns to its reset position, disconnecting the power from the device or machine.

The AK8778B is a reliable, easy-to-install and energy-efficient solid state switch that is ideal for applications in the industrial, automotive, and consumer markets. Its adjustable sensitivity makes it easily adaptable to various applications, and its wide range of uses make it a versatile and valuable tool for any application.