Small though the microswitch is, it has a wide range of applications. From household appliances and electronic products to sophisticated instruments and equipment, micro switches have played a vital role in daily life and scientific research.
How to choose a suitable micro switch for your product? There are six factors you need to take into consideration.
The size of a microswitch is closely related to its characteristics such as current range, travel, and operating force. Here is an example, an ultra-small micro switch measures 7.5mm (L) × 2.5mm (W) ×4.5mm (H). It is commonly used in small video or audio equipment, and other small portable electronic devices like cameras, car stereos, laptop computers, and cell phones. The reason is that it can only break 0.1 to 3 amps of current and has short operating travel.
So when the application is in a higher current situation, is a larger microswitch needed? Usually, This is the case. For instance, the microswitch applied in the fuel is used to detect the liquid level, which must provide long travel and withstand a heavy current. This would require a large microswitch with a current-voltage rating of 125VAC, 20A or 250VAC, 25A. It follows that the smaller the size of the switch, the less travel it has and the less current it can conduct.
2. Current and voltage
It is important to know the current and voltage ratings required for a specific application when choosing the right microswitch. If a microswitch with a low current is selected under conditions where a high current is applied, a short circuit can cause a safety accident. Conversely, a waste of resources can result.
3. Contact material
The contact inside the microswitch is the contact point of the conductive parts during the process of switching. It directly affects whether the microswitch is conductive and determines its life and sensitivity.
The quality of the contact needs to be judged from two aspects. One is to look at the size, generally, the larger the better. And the second is to depend on the material selected, now commonly used materials are silver-nickel alloy, silver-cadmium alloy, and pure silver. Let’s look at the advantages and disadvantages of these three materials contacts.
As can be seen from the table above, the silver-nickel alloy is the most desirable contact material. Although silver-cadmium alloy is not easy to oxidize, the integration of cadmium and silver is not ideal. So under this circumstance, small particles of cadmium metal will form on the contact surface, which may pull out the arc during the conductive process resulting in safety accidents. Meanwhile, cadmium is a kind of heavy metal, prolonged use could cause certain harm to the human body. As for pure silver, it is soft and easy to deform, oxidize and rust, which will reduce the conductivity, and lead to potential safety hazards.
In a word, the choice of contact material in the internal structure for the microswitch affects its quality and practicality. Zhejiang Kangerle Electronics Co. Ltd., a large domestic electronic switch manufacturer, pays great attention to the selection of switch materials. Nowadays, it has provided a variety of high-quality types of micro switches for domestic and international markets.
4. External environment
In critical applications with strict requirements like medical equipment, industrial controls, and aerospace, the option of micro switch should take into account the external environment. You are supposed to know how much dust enters the switch from the air, the type of liquid in which the switch is located, and the temperature of the operating environment.
If applications are under harsh environmental conditions, choosing a sealed micro switch with a wide operating temperature range will matter a lot. It represents that the microswitch has a protection rating of at least IP67 and can also withstand extreme temperatures.
5. Service life
Different switches will be equipped with different contact materials, terminals, and housings according to the life expectancy for each application. Therefore, knowing how many times the service life is required can help you find the right switch for your application.
A reliable microswitch should have an electrical life of no less than 10,000 cycles and a mechanical life of no less than 1,000,000 cycles. Please remember you’re not just paying for one single switch. The most important thing you need to ensure is that the switch will operate trouble-free for a long time.
6. Certification body
It is necessary to understand and check the certification requirements of the authoritative institutions. At present, international electronic certification mainly includes UL in the United States, RoHs in the European Union, TUV in Germany, CSA in Canada, and CQC in China. These certifications all indicate the testing requirements and qualification standards of electronic switches.
If you consider the above six factors, it will be easier to choose the right microswitch. Zhejiang Kangerle Electronics Co., Ltd. develops and manufactures micro switches in various configurations to meet your needs.
Post time: Apr-28-2022