how to connect a micro switch

The microswitch, also known as the sensitive switch or quick switch, is a type of switch with a very small contact interval and a quick action mechanism. Due to its sensitive operation, high reliability and long service life, it is widely used in many fields such as key switches of electronic devices, object position detection, limit control, opening and closing of refrigerator doors, and detection of microwave oven doors. Due to the significant role of microswitches in the aforementioned equipment, the correct connection of microswitches is of certain significance for the normal operation and safety of the equipment. Let's take a look at the relevant introduction of connecting microswitches together

Tools
· Soldering iron and solder wire: The soldering iron is an indispensable tool in the soldering process. It can melt the solder wire by heating, thus achieving a firm connection between the microswitch pins and the circuit board. An electric soldering iron is composed of a base, a casing and other parts. Solder wire is used as the material for soldering. It is placed between the pins and the pads, ensuring a stable electrical connection and mechanical fixation.
· Bevel clamp: When connected to a microswitch, the length of its pins may be too long, which may have adverse effects on the overall layout and installation. Therefore, you can place spacers on the pins and then fix them with screws. The main function of the bevel clamp is to trim the excess parts of the pins to ensure that the pin lengths are appropriate. This not only facilitates its installation and soldering but also keeps the circuit neat.
· Multimeter: After the connection is completed, it is necessary to test the electrical characteristics of the microswitch to ensure that the connection is accurate and the switch operation is normal. The common method is to use a multimeter to test the insulation condition between the contact part and the casing. A multimeter has the ability to measure multiple parameters such as resistance, voltage and current. By analyzing the resistance values of a microswitch in various states, it can be determined whether its normally open and normally closed contacts are in a normal working state.
Material

• Regarding microswitches: There are various models of microswitches on the market, and these different models vary in size, contact capacity, and the force of action. Due to the different application scenarios and functional requirements, their installation positions also vary, thus putting forward higher demands on the performance of microswitches. Therefore, when choosing the model of a microswitch, it is necessary to take into account the specific application environment and the specific requirements of the circuit. Both excessive and insufficient contact resistance can have adverse effects on the entire system. Therefore, it is necessary to reasonably select the specification parameters of the microswitch. For instance, in industrial equipment that needs to withstand large currents, it is very necessary to choose microswitches with larger contact capacity. For those electronic devices with limited space, it is necessary to choose smaller-sized microswitches.
• Circuit board: As the connection tool for microswitches, the circuit board needs to be appropriately matched with the microswitch. Therefore, when designing, it is necessary to ensure that its electrical characteristics meet the requirements of microswitches. The layout of the pads on the circuit board should match the pin positions of the microswitch to ensure the smooth progress of the soldering process. In case of malfunction or damage, maintenance personnel can remove the circuit board from the microswitch for repair. In addition, the material and quality of the circuit board will also have an impact on the soldering effect and the stability of the circuit.
• Optional wires: In certain situations, the microswitch may not be directly soldered onto the circuit board but rather requires the use of wires for connection. Wires can be made of different materials and shapes. For instance, when the distance between the microswitch and the circuit board is too far or flexible adjustment is required during connection, the wires play a crucial role. Wires are composed of a single wire or a combination of two or more wires, among which one is a conductive wire and the others are insulators. During the process of connecting with wires, it is necessary to carefully select wires that meet the appropriate specifications and carry out proper insulation treatment to avoid short circuits

Get to know the pins of microswitches
The common pin types of microswitches include normally open (NO), normally closed (NC), and common (COM) pins. Among them, the normally open pin is the most commonly used and widely applied type of pin. When the switch is not yet activated, the normally open pin will automatically open, but when the switch is activated by an external force, the normally open pin will form a connection with the common pin. On the contrary, the normally closed pin is on when the switch is not activated, but is disconnected from the common pin when activated. The common pin is a normally open pin and does not participate in the switching current. The common pin, serving as the shared connection point for both normally open and normally closed pins, plays the role of a bridge in the entire circuit system. Because their working principles are the same, the normally open or normally closed pins can be used to determine whether the microswitch is operating normally. To connect microswitches correctly, it is crucial to understand the changes in the electrical state of different pins during the switching process.
Connection steps

• Select the connection method: Based on the specific requirements of the circuit, decide to use a microswitch as a normally open, normally closed switch, or a combination of both. Under normal circumstances, to ensure that the access control system has high reliability and stability, as many design methods as possible should be adopted. For instance, in a simple doorbell circuit design, when a user presses the doorbell button (microswitch) and hopes to hear the doorbell sound, they can choose to connect the microswitch as a normally open switch. In this way, the normally open pin and the common pin can be connected to the circuit. This design is intended to meet the feature that the gate control part has a relatively low requirement for delay time. In some circuit designs that require interlocking characteristics, to achieve specific control objectives, both normally open and normally closed pins may be used simultaneously.
• Soldering steps: First, the soldering iron needs to be heated to an appropriate temperature. At this point, place the welding head in the welding seat and turn on the power to heat the welding head. Next, melt a small portion of the solder on the corresponding pads of the circuit board, thereby generating a evenly distributed solder layer on the surface of the pads. At this point, place the microswitch above the pad to perform the welding operation. Then, place the pins of the microswitch on the pad, heat the soldering iron again to melt the solder and completely wrap the pins, ensuring a good electrical connection and mechanical fixation between the pins and the pad. During the welding process, we need to pay special attention to the welding duration and temperature to prevent excessive heating from causing damage to the microswitch or circuit board. Under normal circumstances, the welding duration should not be too long. The optimal welding time is 2 to 3 seconds for each welding point.
• Regarding wire connection (if applicable) : When it is necessary to use wires to connect a microswitch and a circuit board, first remove an appropriate length of insulation from one end of the wire. Then, wrap the stripped end around the pins of the microswitch and solder it with an electric soldering iron to ensure the firmness of the soldering. The terminal block between the wire and the microswitch can be made of materials such as copper bars or aluminum sheets, but it must be ensured that the wire will not be burned out. Then, the other end of the wire needs to be connected to the corresponding position on the circuit board, and ensure that the soldering process is properly handled. In this way, an electrical circuit is formed between the wire and the microswitch. When making connections, be sure to pay attention to the direction of the wires

Safety Matters

• Prevent electric shock: Before starting the connection operation of the microswitch, make sure the power supply has been disconnected. If there is a possibility of leakage, the power supply should be cut off in time and checked for any abnormal phenomena such as electrical leakage or short circuit, so as to facilitate correct operation. Before starting the operation, you can use a multimeter to measure the voltage of the circuit and proceed with the operation only after confirming that the voltage is zero. If there is a leakage of electricity, the power plug should be cut off immediately and the contact head should be inserted into a grounded socket. Please avoid any connection operations when the power is on to prevent electric shock accidents and thus avoid posing a threat to personal safety.
•  Prevent scalding: The temperature of an electric soldering iron during operation is extremely high, usually reaching several hundred degrees Celsius. If it accidentally comes into contact with the skin, it will cause local burns and even lead to burns. Therefore, when using an electric soldering iron, be sure to avoid burns and wear special protective gloves during the operation. After completing the operation, be sure to quickly turn off the power of the soldering iron and ensure it is in a safe position to prevent others from touching it and getting burned.
•  Prevent static electricity: When working in a dry environment, the human body may generate static electricity. If one remains in this state for a long time, it is very likely to cause pain and numbness in the hands or fingers, and even lead to electric shock accidents. Static electricity may cause damage to microswitches and other electronic components, thereby affecting their performance and service life. If one is exposed to electrified objects for a long time, it can also cause skin damage or lead to diseases such as dermatitis and eczema. Therefore, we should take measures to prevent static electricity, such as wearing a special anti-static wristband and ensuring that the other end of the wristband is in close contact with the ground, so as to promptly eliminate static electricity from the human body.

Operating Specifications

•  Regarding the standards for welding: Ensuring the duration and temperature of welding is of vital importance. When the specified requirements are exceeded, protective measures need to be taken to prevent local tissue softening caused by overheating or overcooling, which may lead to defects such as cracks. As previously described, the soldering time is usually limited to between 2 and 3 seconds, and the selection of soldering temperature should be based on the melting point of the solder wire as well as the heat resistance characteristics of the circuit board and microswitch. When solder is overheated, it will flow, which may cause the solder joints to become incomplete and even damage the components. If the heating is not sufficient, the solder may not melt completely, which will have an adverse effect on the quality of the soldering.
• Regarding the handling of pins: During the process of trimming pins, appropriate tools such as diagonal pliers should be used, and it should be ensured that no other components or wires are accidentally cut. If it is necessary to cut off the lead wires, you can use tweezers to hold a broken wire and cut it, or you can use scissors to cut a part in the middle as a new lead wire. After trimming the pins, ensure they are neat and maintain an appropriate length, usually not exceeding 2-3mm from the edge of the circuit board. If there are burrs on the pins or there are many solder joints, an electric soldering iron can also be used to solder the pins clean. The neat pin design not only makes installation and soldering simple, but also enhances the appearance and stability of the circuit.
• After testing and verification, once the connection is completed, we use a multimeter to evaluate the electrical characteristics of the microswitch. Install the sensor on the microswitch for the experiment. We can independently measure the resistance values of the normally open and normally closed contacts of the microswitch in both the off and on states. If the contact is not in place, it indicates poor contact and requires inspection, repair or replacement with a new microswitch. Under normal circumstances, if there is no action, the resistance of the normally open contact should be infinitely large, while the resistance of the normally closed contact should be close to zero. When in operation, the resistance value of the normally closed contact is less than that of the normally open contact. However, when it comes to performing the action, the situation is completely the opposite. The causes of phenomena such as poor contact of microswitch contacts and unstable contact voltage were analyzed, and corresponding improvement measures were proposed. After a series of tests and verifications, we ensured the correctness of the connection and the normal operation of the switch, thus being able to identify and handle potential problems in a timely manner

Conclusion

To connect a microswitch, you need to prepare tools such as an electric soldering iron, solder wire, diagonal pliers and a multimeter. At the same time, you also need related materials such as a microswitch, circuit board and optional wires. The microswitch is a commonly used electrical appliance. Its use and installation are very simple and convenient. However, if it is not used and installed correctly as required, it may lead to poor contact and damage, and even cause accidents. When making connections, we need to accurately understand the pin types and electrical condition changes of the microswitch, and operate according to the set connection method, soldering connection or wire connection process. At the same time, it is necessary to strictly follow the safety measures to prevent electric shock, scalding, static electricity, as well as the operation norms such as welding standards, pin handling, and test verification. In addition, it is necessary to master the correct usage method based on the working principle of the microswitch. Only when these regulations are strictly followed in the actual operation process can the connection quality and safety of the microswitch be guaranteed, thereby ensuring the normal operation of the equipment. In view of this, the article mainly analyzes the key points and precautions of the connection technology of microswitches for reference and learning. We hope that the content of this article can provide certain guidance for readers when connecting microswitches, inspiring them to continuously accumulate experience and improve their operational skills in the actual operation process.