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Where is a reed switch used?
Reed switches actuated by magnets are commonly used in mechanical systems as proximity sensors. Examples are door and window sensors in burglar alarm systems and tamperproofing methods. Reed switches have been used in laptops to put the laptop into sleep/hibernation mode when the lid is closed.
How does an electric reed switch work?
How Does a Reed Switch Work? The switching mechanism is comprised of two ferromagnetic blades, separated by only a few microns. When a magnet approaches these blades, the two blades pull toward one another. Once touching, the blades close the normally open (NO) contacts, allowing electricity to flow.
Are reed switches normally open?
reed switch and sensor. Recall that the natural state of a form A reed switch is normally open. It can be turned into a normally closed switch by applying a permanent magnet with a field strong enough to close the reed contacts.
How much current can a reed switch handle?
On larger evacuated Reed Switches, ratings as high as 15,000 Volts DC are not uncommon. Some smaller evacuated reeds can stand off up to 4000 Volts DC. Small pressurized reed switches generally withstand 250 to 600 Volts DC.
How do you use a reed switch?
A reed switch like this is normally open (NO) (normally off), unless a magnet is positioned right next to it, when it switches on, allowing a current to flow through it. Take the magnet away and the contacts—made from fairly stiff and springy metal—push apart again and return back to their original positions.
What are the advantages of reed switch?
Simple and reliable sensing and actuation capabilities. Low-profile designs for ease of integration within space constrained environments. Zero power requirements for operation. Durability and performance over extended service life.
How reliable are reed switches?
Reed relays are considered to be the most reliable mechanical relay solution for low power switching. They have few moving parts and an inherently long mechanical life. However, not all reed relays are constructed to the same high standards.
Do reed switches need a resistor?
The functioning that resistor is to protect your logic board from surges, but not be so high that it impedes a clean signal. You need a 100k pull UP resistor between the Reed switch and r1, connecting to 3.3v. Otherwise your signal on D5 will float and your board will not know if the Reed switch is closed or not.
How fast are reed switches?
A reed switch is a mechanical device and, therefore, the switching speed is low compared to electronic switches (typically 0.2 ms turn-on time, 0.02 ms turn-off time).
What can I use instead of a reed switch?
Like a reed switch, the Hall-effect sensor actuates when a magnet comes in range of the device. One of the biggest advantages of Hall-effect sensors is that they are solid state and immune to wear, shock and vibration. Switch bounce is also not an issue as there are no moving parts in the solid state sensor.
What are the advantages in using reed switches?
Fully hermetically sealed metal contact.
What is use of reed switch in electronics?
Reed switches have been used in laptops to put the laptop into sleep/hibernation mode when the lid is closed . Speed sensors on bicycle wheels frequently use a reed switch to actuate briefly each time a magnet on the wheel passes the sensor. Reed switches were formerly used in the keyboards for computer terminals, where each key had a magnet and a reed switch actuated by depressing the key.
What is a magnetic reed switch?
The reed switch is an electrical switch operated by an applied magnetic field. It was invented at Bell Telephone Laboratories in 1936 by Walter B. Ellwood.
What is a door reed switch?
A magnetically operated reed switch such as this is commonly mounted on doors and windows to add protection to a home or business. The switch is small and discreet enough to mount in a home or office without being noticeable.