A Guide to Reed Switches
If you go to a modern factory, you will find many amazing electronics at work in an assembly cell with many sensors involved. These sensors are composed of several wires including wires for voltage supply, ground, and signal. The sensor will do its job if you apply power to it. The reed switch can be used to trigger these sensors. And only two wires are used to do the job. with the use of magnetic fields, the reed switch can be activated.

Reed switches are small items that look like a glass capsule. ON each end there is an electrical lead that pokes out.

The reed switch has to magnetic blades that are separated by a small distance. When a magnet passes near the blades, they attract each other and touch. This closes the circuit and allows electricity to flow. On the other hand, there are reed switches that work the other way around. If a magnet approaches the reed switch the contact will disconnect and pull away from the switching contact and electricity will be cut off. Read more

These contacts are made of different kinds of metals including rhodium and tungsten. Others use mercury. And in order to switch correctly, they must be kept if proper orientation. Inert gas like nitrogen fills the glass envelope. The contacts are sealed. It prevents corrosion and if there is any contact movement, sparks are also prevented. 

Sensors are found in items we see every day like washing machines and cars. But one of the best places to put a sensor or switch is in burglar alarms. This technology works perfectly with burglar alarms. If you have a moveable window or door with a magnet and a sensor on the base, then the removal of the magnet will pass a signal. So if the window is opened or someone cuts the wire, the alarm will sound. Burglar alarms are excellent use for reed switches. 

Reed switches can be activated even without the use of a permanent magnet. You can switch them on with an electromagnet relay. Read on tilt switch

Because of closed contacts, these reed switches face less electrical resistance. They can work with different voltages, frequencies, and loads because of the simple switch function as connected or disconnected wire.

Before a reed switch fails, it can function for billions of cycles so they are very reliable for a switch. And since they are constructed in a sealed environment, they can operative in environments that are explosive where even a small spark can bring about results which are disastrous. Reed switches are far from obsolete even though it is old technology. 

If you are building a circuit, don’t forget a reed switch. It does can do its basic switching job is a very simply manner. You can always rely on a reed switch's design which is tried and tested to work consistently. View https://www.youtube.com/watch?v=_sgU7vi9w6M