The hang up and answering switch in the headset is divided into normally open type and normally clos

Look at this and you'll understand.

In fact, there are three main types of devices used in mobile phones to control the line on/off: switches, reed switches, and Hall elements. The difference is that the switch is generally manually controlled by humans, while the reed switch and Hall element control the line on and off through magnetic signals.

A reed switch is a passive electronic component that is widely used in a variety of communication devices. It is a kind of line switching device that uses magnetic field signals to control, also known as "magnetron". The shell of a reed tube is usually a sealed glass tube with two iron elastic reed plates in the glass tube, and an inert gas called rhodium metal is also filled into the glass tube.

Usually the two reeds in the glass tube are separated, when there is a magnetic substance close to the glass tube, under the action of the magnetic field lines, the two reeds in the tube are magnetized and attract each other to contact, so that the circuit connected to the two pins is connected. After the external magnetic force disappears, the two reeds are separated due to their own elasticity, and the line is also disconnected, in practical use, permanent magnets are usually used to control the connection of these two metal sheets, so it is also called "magnetron". Magnetrons are often used in mobile phones and are often used in mobile phone clamshell circuits, especially Motorola mobile phones.

Through the action of the flip cover, the magnet on the flip can control the magnetron to close or disconnect, so as to answer or hang up**. For example, some Motorola mobile phones will have a status indicator light flashing after closing the cover, which is due to the fact that the flap is equipped with a magnet sheet, when the flap of the phone is closed, the magnet sheet will be the reed switch on the keyboard display board to suction, so that the phone recognizes that the flap has been closed, and the status indicator light begins to flash. If this indication does not light up, it is most likely that there is a problem with the reed.

At present, magnetrons basically use the technology of the Japanese company OKI. Hall sensors are a bit more advanced than reed switches. However, its role in mobile phones is the same as that of reed switches, and its working principle is very similar, both of which directly produce on-off and on-off effects under the action of magnetic fields.

A Hall sensor is an electronic component with a package that closely resembles a transistor. It is composed of a hall element, an amplifier, a Schmitt circuit and an open-collector output transistor, when the magnetic field acts on the hall element to produce a small hall voltage, the amplifier amplification and Schmitt circuit make the triode turn on the output low level, and when there is no magnetic field (that is, after the flip cover is opened) the triode cut-off output is high. Compared with reed transducers, HALL sensors have a longer lifespan, are not easily damaged, and are less sensitive to vibration and acceleration, and the switching time is relatively fast, usually much faster than 1 3ms of a reed transit.

Let's take Ericsson's classic mobile phone T39MC as an example, and talk about how the mobile phone flip cover works. At the same time, this principle also applies to other folding and clamshell machines.

My heart flutters" is not right.

The question is the principle of the switch in the headset, and the bull's head is not in the horse's mouth.

I would also like to know how the headphone switch works.

Switches are divided into normally open type and normally closed type?

So far in 2020, the ranking according to the comprehensive performance and cost performance of mobile phones:

Xiaomi Mi 9 Pro 5G

Huawei P30Pro

Apple 11Pro

Black Shark Gaming Phone 2 Pro

Xiaomi CC9Pro

vivo iq00 pro

OnePlus 7T Pro

Honor V30Pro

ROG Gaming Phone 2

realmex2 pro

Personally, I feel that there are a few kinds of around. First: Huawei includes his Honor phone. Second: Apples. Thirdly, Xiaomi phones. Fourth, vivo as well as OPPO. Further down is the Samsung series. The rest are rare.