What is a SPDT switch and what is the use of a SPDT switch

There is only one switch, but there are two circuits, the upper is the circuit, and the lower is the circuit!

This is the circuit diagram, and that k2 is to start the double-throw operation.

The single-pole double-throw switch is composed of a moving end and a fixed end, the moving end is the so-called "knife", which should be connected to the incoming line of the power supply, that is, the end of the incoming call, which is generally the end connected to the handle of the switch; The other two ends are the two ends of the power output, the so-called immovable end, which are connected to the electrical equipment. It is a SPDT switch.

First, it can control the power supply to output in two different directions, that is to say, it can be used to control two devices, or it can also control the same device to switch the direction of operation.

There is only one switch, but there are two circuits, to the left is to tube this circuit, and to the right is to tube that circuit!

The single-pole connection is the outgoing line of the power supply, and the two ends of the double-throw switch are the two ends of the power input. It is used for self-generation and conversion between mains power. used for switches.

A switch can control two branches, that is, the part of this circuit is controlled by two branches and a switch, and the circuit is different if the switch connection method is different.

High power, low loss, fast and low cost, it has become the main device of medium and small power switching.

Double-pole double-throw switches are a type of coaxial switches, defined by the number of interfaces, codenamed p t, and there are also single pole single throw (SPST), single pole double throw (SPDT), single pole six throw (SP6T), etc.

The devices that make up a coaxial switch are ferrites, pins, FETs, or BJTs. Ferrites and pins are classic switching devices, Table 1 shows the performance comparison of the two devices, ferrite is characterized by high power and low loss, PIN is characterized by fast and low cost. FETs or BJTs have gain and have become the main components for medium and low power switching.

Coaxial switches of various devices have their own use cases.

What the DPDT switch does:

Two switches control a light source at the same time, which is convenient for people's lives.

Home circuits are often used in stairs, generally a switch is upstairs, another switch is downstairs, two switches are the same as a light source, downstairs switch turns on the lighting when going upstairs, upstairs after the upstairs switch turns off the light source, and vice versa downstairs is the same.

It can be seen that the big role of the double-pole double-throw switch is to facilitate life, in the case of long-distance lighting, it is inconvenient to turn off the light is not as good as not to have the lamp, if there is only one switch, then either it can only be on all the time, or there is someone at that end to turn it off, or it is not used at all, choose other lighting methods to move forward.

Precautions for installation of double-open double-throw switches:

1. You can set up some sockets with switches, so that you don't need to pull out the plug and cut off the power supply, and the unplugged wires will not affect the appearance, such as the washing machine socket can be closed when not in use, and the air conditioning socket can be closed in the off-season without unplugging;

2. Do not install the kitchen socket on the stove to prevent overheating;

3. Install the bathroom bath bomb switch, remember to leave a few more centimeters, because this switch is generally larger than the switch of the lamp, if it is almost impossible to install it, it will be troublesome;

4. Install the switch in a place where the water is too much, if it is installed on the open balcony, remember to use the special splash-proof cover of the switch and socket;

5. Consider the socket and corresponding control switch of the lights in the bookcase and cabinet;

6. Consider the sockets and corresponding control switches for burglar alarms, gas alarms, wall-mounted LCDs, entrance lights, etc.

The more common use of double-pole double-throw switch is the switch of the staircase light in the home circuit--- one switch is upstairs, one switch is downstairs, as long as the light is on, no matter which switch is toggled, the light can be turned off; As long as the light is off, the light can be turned on no matter which switch is flipped.

A SPDT switch is an electrical switch, usually consisting of a fixed, insulated base stool and a movable switch component, which is used to control the on/off and conversion functions in a circuit. SPDT switches have three contacts, one of which is a common contact and the other two are switching contacts. When the switch is in one position, the common contact is connected to one of the switching contacts, while the other switching contact is disconnected.

When the switch is switched to another position, the common contact is connected to the other switching contact, and the previous switching contact becomes disconnected. SPDT switches are often used for the conversion and control of circuits, and can play a good role when switching between multiple power supplies or loads, such as switching the main and standby power supply of UPS equipment, switching lighting scenes, adjusting the forward and reverse rotation of motors, etc.

1. The double-pole double-throw switch is actually two single-pole double-throw switches in parallel, and its wiring method is exactly the same as that of each single-pole double-throw switch, and the two knives are connected by an insulating plastic, and then share a handle.

2. Each side of the double-pole double-throw switch is equivalent to a single-pole double-throw switch, which can be used as two single-pole double-throw switches; The two adjacent binding posts on the same side of the DPST switch are equivalent to a SPST switch, which can be used as four SPST switches.

3. Due to the different wiring methods of A, B, A, and B, the double-pole double-throw switch will have different functions: such as changing the direction of current or voltage, exchanging the position of electrical components, etc.