The switch is a very common one. In our daily life, whether in industry, medical equipment, security equipment, amusement equipment, household appliances, office automation equipment and cars, planes, ships, keyboard, digital converter, children's toys and industrial automation systems, even a cutting-edge space technology and military equipment of the operating system, etc., all of the electronic products have the switch.
1. Function of the switch
In electronic equipment, switches are used to put on, cut off, or change circuits to change the operating state of the equipment. Such as communication machine change band, frequency, television receiver change channel, recorder transform function, measuring instruments change range and all kinds of circuit control.
2. Structural characteristics of the switch
The vast majority of switches are made up of enclosures, insulation sheets, handles, contacts, lead devices, reset springs (self-locking devices), and fasteners. The shell and insulation sheet are molded by ABS engineering plastic and insulating bakelite. Handle, return spring, fasteners are made of metal processing; The material of lead device mostly uses copper alloy; The contacts used for switches are generally made of silver copper alloy or pure silver.
3. Switch type
(1) According to the pole classification, can be divided into unipolar switch, bipolar switch and three pole switch: switch "pole" corresponds to the past called "knife", "bit" corresponds to the past called "throw", such as bipolar double position switch is double knife double throw switch. The pole of the switch is actually equivalent to the active contact of the switch (contact head, contact knife), and the bit is equivalent to the static contact of the switch (contact). When the switch is pressed or towed, the active contact is connected (or disconnected) with the stationary contact, thus playing the role of connecting or disconnecting the circuit.
Because a unipolar unit switch has only one active contact and one stationary contact, only one circuit can be connected or disconnected. The single-pole two-position switch can choose to turn on (or turn off) one of the two circuits; Bipolar two-position switch can connect or disconnect two independent circuits at the same time; The functions of other pole switches can be similarly deduced.
(2) The action mode of pressing the switch is divided into key switch, DC switch, lever switch, DIAL switch, push open switch and rotary switch.
(3) According to the structural characteristics of the switch, it can be divided into straight key switch, key switch, button switch, slide switch, ship switch, nut switch, key switch, key switch and band conversion switch.
(4) According to the control mode, it can be divided into proximity switch, timing switch, infrared photoelectric switch, Hall switch, human infrared sensor switch, magnetic switch, etc.
Switch classification is only one form, not the only one. What is important is the switch that chooses which kinds of means specifically, want to come up not only from the technical requirement of circuit consideration, and want the beautiful sex that arranges from whole machine face plate and the convenient sex of operation to consider.
