How to Wire Micro Switch

Micro Switch is a precise and small electrical switch widely used in industrial automation, household appliances, automotive electronics and medical equipment. Due to its high sensitivity and durability, it plays a key role in circuit control. However, many users may encounter confusion when wiring. This article will introduce the wiring method of micro switch in detail to ensure that you can complete the connection correctly and safely.

Internal Structure Of Micro Switch

If you want to connect the micro switch accurately, you must know the structure of the micro switch to avoid connecting the wrong terminals. If you already know how to distinguish the terminals, please skip this section. The micro switch is mainly composed of the following core components:

Actuator: used to start the switch operation, such as a button, lever or roller.

Snap-action Mechanism: The core component for quickly switching the switch state.

Contacts: Control the switch state of the circuit, usually with three types of terminals.

Terminal Introduction

Standard micro switches usually have the following three terminals:

• ●COM (common terminal): main connection point, usually connected to power supply or load.
• ●NO (normally open terminal): disconnected from COM terminal when the switch is not pressed; when the switch is pressed, NO terminal and COM terminal are closed to form a path. Suitable for circuit control that needs to be triggered by pressing.
• ●NC (normally closed terminal): when the switch is not pressed, NC terminal and COM terminal remain connected; when the switch is pressed, NC terminal and COM terminal are disconnected. Suitable for circuit control that needs to be disconnected by pressing.

The distribution of these three terminals is shown in the figure below. After understanding the functions of these three terminals, let's start preparing for wiring.

Preparation For Connecting The Micro Switch

Before starting the wiring, it is recommended to prepare the following tools and materials to ensure a smooth connection:

1. Prepare the micro switch. Prepare the micro switch. Before wiring, make sure the micro switch is available and make sure the switch type matches. Because the micro switch has a variety of circuit types, such as SPST, SPDT, DPST, DPDT.
2. Prepare the wire. It is recommended to use high-quality copper wire with good insulation performance, and first strip off the insulation layer of a section of the wire to expose the copper wire inside.
3. Screwdriver. Prepare a suitable cross or flat screwdriver and select the matching tool according to the screw specifications of the switch mounting hole.
4. Multimeter, used to measure the on-off state between the terminals. Use the multimeter to check the on-off state of the micro switch before and after wiring to ensure that the wiring is correct.

How To Connect a Micro Switch With Wires

Step 1: Identify The Terminals

Use a multimeter to measure the terminals of the switch and the introduction in the first paragraph to determine the positions of the COM, NO, and NC terminals.

Step 2: Connect The Com Terminal

Connect the input terminal of the power supply or load to the COM terminal of the micro switch.

Step 3: Select The No Or Nc Terminal

If you want the circuit to be connected when the switch is pressed, connect the input terminal of the load or control device to the NO terminal. If you want the circuit to be disconnected when the switch is pressed, connect it to the NC terminal.

Step 4: Fix The Wire

Fix the copper wire with a screw connection to ensure that the wire is firmly connected to avoid disconnection due to vibration or external force.

Step 5: Test the connection

After completing the connection, use a multimeter to check the on-off condition of the micro switch to ensure that the connection is correct.

Other Ways To Connect Micro Switches

In addition to directly connecting with wires, there are many ways to use in different application scenarios:

Welding Connection

Welding connection is suitable for electronic devices or switches that are used for a long time, ensuring firmness and reducing the risk of poor contact.

1. Prepare tools and materials

Choose a suitable micro switch, electric soldering iron (recommended 30W-60W), lead-free environmentally friendly solder, flux and wire. In addition, auxiliary tools such as tweezers and solder extractors can be used.

2. Wire stripping

First, strip 5-7mm of the insulation layer of the wire to be connected, ensure that the copper wire is exposed and twisted tightly to enhance conductivity and welding stability.

3. Pre-treat the terminal

Applying a small amount of flux on the micro switch terminal can effectively remove the oxide layer, improve the welding quality, and prevent cold welding or false welding.

4. Heating welding

After heating the terminal with an electric soldering iron for 1-2 seconds, gently touch the solder wire to the connection between the terminal and the wire, so that the solder flows naturally and evenly wraps the contact point, ensuring that the solder joint is full and smooth, without the risk of excess solder short circuit.

5. Cooling and inspection

After welding, let the solder joint cool naturally, do not shake or touch to avoid cold solder joints. Then use a multimeter to test whether the connection is stable to ensure that the micro switch functions normally.

6. Fixing and insulation

If the solder joint is exposed, it should be wrapped with heat shrink tubing or electrical tape to prevent short circuits and improve safety. Finally, make sure the switch is firmly installed to avoid vibration that affects the reliability of the solder joint.

PCB Board Installation

On the printed circuit board (PCB), the micro switch is usually installed by plug-in welding. This method is often used in home appliance control boards, smart homes and industrial automation controllers.

1. 1.Prepare the PCB board

When designing the PCB layout, ensure that the terminal holes of the micro switch are accurately matched, and mark COM (common terminal), NO (normally open terminal) and NC (normally closed terminal) to prevent wrong connection.

2. 2.Insert the micro switch

Insert the metal terminal of the micro switch into the corresponding pad on the PCB board, and ensure that the terminal is fully inserted to ensure that the welding is firm.

3. 3.Welding fixation

Use an electric soldering iron (recommended 30W-60W) to heat the pad and terminal. When the temperature is suitable, add an appropriate amount of lead-free solder to evenly wrap the terminal. The solder joint should be smooth and full to avoid cold soldering or false soldering.

4. 3.Check the welding quality

After the welding is completed, check whether the solder joint is firm, and use a multimeter to measure the on-off status of the COM, NO, and NC terminals to ensure that the switch functions normally.

5. 4.Installation and fixing

In some applications, it may be necessary to fix the micro switch additionally, such as using screws or glue to enhance stability and prevent poor contact caused by vibration.

Connector To Micro Switch

This is what we call a quick connection method. Compared with welding, this method is gentler and is a safe, removable and easy-to-maintain method for applications such as industrial control, home appliances and automotive electronics.

1. Prepare tools and materials

Choose the appropriate micro switch, terminal connector, terminal crimper (or wire stripper), screwdriver (if using screw terminals), heat shrink tubing or electrical tape to enhance insulation.

2. Choose the type of connector

• Terminal crimp connector(suitable for environments with large vibrations, such as automotive electronics): fix the wire to the metal terminal by crimping and then insert it into the plastic housing.
• Plug-in terminal (suitable for frequently replaced equipment): directly insert the wire into the terminal hole without soldering, and can be replaced or repaired at any time.

3. Screw terminal(suitable for industrial control systems): fix the wire by tightening the screw to ensure a stable connection.
4. Stripping and crimping terminals

First remove 5-7mm of insulation with a wire stripper to ensure that the copper wire is exposed to an appropriate amount. If you use a terminal crimping connector, insert the copper wire into the metal terminal and clamp it with a crimping tool to ensure good contact and no loosening.

5. Connect the micro switch terminal

• ●If you use a terminal crimping connector, insert the terminal into the corresponding terminal of the micro switch to ensure stability.
• ●If you use a plug-in terminal, directly insert the wire into the corresponding COM, NC or NO terminal to ensure good contact.
• ●If you use a screw terminal, tighten the wire with a screwdriver to ensure that it is firmly fixed but does not damage the copper wire.

6. Fixing and insulation

After the connection is completed, wrap the exposed part with heat shrink tubing or electrical tape to prevent short circuit or oxidation. Make sure all connections are firm and reliable to avoid loosening due to vibration or external force.

Conclusion

As long as you understand the structure of the micro switch, it will be very simple to connect the micro switch. If you don’t know how to operate it correctly, please feel free to contact us for more information.

If you are looking for a reliable micro switch, welcome to visit Unionwell for more product information. We have more than 20 years of experience in producing micro switches, providing reliable switches, flexible delivery time and affordable factory prices!