What is a balanced magnetic switch?

What is a balanced magnetic switch?

A balanced magnetic switch consists of a switch mounted to a door (or window) frame and a magnet mounted to a moveable door or window. When the door is closed, the magnet holds the switch closed to complete an electrical circuit. An alarm is triggered when the door is opened and the circuit is interrupted.

Are magnetic switches reliable?

Thanks to the use of only one single “active” component (reed contact), “traditional” electromechanical magnetic switches are extremely reliable in operation. The universal current capability and low procurement costs allow these switches to be used in a wide range of applications.

When would you use a magnetic switch?

Simple magnetic switches are used to detect the opening of doors and windows. A basic magnetic switch comprises two parts— the magnet and a magnetically sensitive switch (usually a reed switch enclosed within a glass envelope). Switches may be either normally open (close on alarm) or normally closed (open on alarm).

What is a triple biased reed switch?

• Triple-biased, SPDT (Form C) reed alarm switches in the switch. unit with a magnet array in the magnet unit, makes the defeat of. the switch with an external magnet virtually impossible. • Magnetic field tamper output added to further resist defeat with. an external magnet or magnet array assembly.

Why do reed switches fail?

Reed switches or relays eventually fail in one of three ways . They do not open when they should (usually called “sticking”), they fail to close when they should (“missing”), or their static contact resistance gradually drifts up to an unacceptable level .

Does polarity matter for reed switch?

It can be turned into a normally closed switch by applying a permanent magnet with a field strong enough to close the reed contacts. This biasing magnet must be greater than the pull-in field or operate field that closes the contacts in the normally open condition. The polarity of the magnet does not matter.

Does polarity matter for Reed Switch?

What is a bias magnet?

A bias is a permanent magnet placed near a reed contact to oppose or aid its operation. Normally-closed reed contacts use a biasing magnet to oppose the actuating magnet. Latching reed contacts use a biasing magnet that aids and opposes the latch and unlatch operations by the actuating magnet.

Does a reed switch need a resistor?

A Reed Switch has very low resistance when closed, typically as low as 50 milliohms hence a Reed Switch can be said to require zero power to operate it.

What can I use instead of a reed switch?

You could use a hall-effect sensor; you could also use an optical sensor of some sort (you would likely need to use modulated IR light to prevent interference from external light sources)…

How much current can a reed switch handle?

Switching current of a reed contact, measured in Amperes, is the maximum current a reed contact can switch. The switching current of a reed contact can range from as low as 1 fempto-amp up to 5A using special contact materials.

What causes exchange bias?

The exchange bias effect is attributed to a ferromagnetic unidirectional anisotropy formed at the interface between different magnetic phases. Generally, the process of field cooling from higher temperature is used to obtain ferromagnetic unidirectional anisotropy in different exchange bias systems.