The tact switch is a kind of electronic switch, which belongs to the electronic components category.
Tact switches are also known as push button switches. In an electrical automatic control circuit, a certain operating force is manually applied in the direction of the switch operation to turn the circuit on. When the pressure is removed, the circuit is disconnected. Simply put, a tact switch is a switch that can be turned on instantly by pressing it gently.
Tact switch mainly consists of pins, contacts, base, reed, dust-proof film, cover-board, and button. The waterproof type will add a layer of polyimide sub-film to the reed.
Tact switch has many advantages such as slight operating force error, small contact resistance load, diversified specifications, and good hand feeling.
The application of tact switches can be seen everywhere in life and is widely used in the following areas.
1. Mobile devices: cell phones, laptops, tablets
2. Electronic accessories: headphones, electronic watches, smart bracelets, portable game consoles
3. Digital products: digital cameras, digital cameras
4. Household appliances: TV sets, microwave ovens, air fryers, rice cookers
5. Audio-visual equipment: MP3, MP4, DVD speakers
6. Remote control: remote control door lock, electric rolling door remote control
7. Car equipment: car navigator, instrument panel
8. Toy supplies: electronic button toys, light strings
9. Fitness equipment: treadmill, massage chair
10. Medical equipment: ward call intercom system, electronic blood pressure meter, electronic thermometer
11. Security products: visual intercoms
Rated Load: 50mA DC12V
Contact Resistance: ≦50mΩ
Insulation Resistance: ≧100mΩ
Electrical life: ≧100000 times
Operating Force: 250gf±50gf
Return force: 50gf/min
Stroke: pressing with twice the operating force, the stroke is 0.25±0.1mm (As shown in the picture)
Different products have different parameters performance, to look specifically at what is used to select the right product. In addition to the above performance, we also need to see some other test results to check whether a tact switch is qualified. For example, solderability, vibration resistance, heat resistance, cold resistance, humidity, salt spray, and life of the test.
Since tact switches are used everywhere in daily life, how do you make a judgment of the good or bad quality? The following factors can provide reference and help to select a good quality tact switch.
1. Pin material
The pin material of the tact switch is brass or phosphor bronze, if it is iron, it is of low grade. At the same time, the pins are also silver-plated in order to reduce contact resistance. Because sulfur dioxide gas in the air oxidizes silver, which directly affects the solderability and contact resistance of the switch. A high-quality tact switch is very much a test of the thickness of the silver plating on the pins and the control of the silver plating process. With a good silver plating treatment, you should also pay attention to whether the switch has the function of dustproof and waterproof. Otherwise, the switch will still be oxidized.
2. Contact size
The function of the tact touch switch is achieved by connecting the contacts and reeds. Therefore, the size of the contact directly affects the on-off stability of the switch. The larger the contact, the better. But it is best not to exceed half of the tact switch area, otherwise, it will get stuck and thus affect the circuit’s on-off condition.
3. Contact material
Contact materials are usually brass, pure silver, silver-nickel alloy, and silver-cadmium alloy. Brass material is easy to produce sparks, shortening its life, so basically no longer used. Pure silver has low resistance and good conductivity, but it is soft and easy to oxidize, rust, and deform, so as to reduce the conductivity. In serious cases, it will produce an arc and cause a fire. The silver alloy has strong electrical conductivity, wear-resistant texture, and oxidation resistance, so its comprehensive performance is superior to that of pure silver.
4. Stroke, reed
The combination of the stroke and reed determines a tact switch’s life and feel. The shorter the stroke, the quieter the sound, and the longer the life. Secondly, the advantages and disadvantages of the material of the reed affect the sensitivity of the tact switch conduction performance. Good materials include silver-covered copper and stainless steel.
5. Production process
Each factory’s machinery and equipment, process, staff quality awareness, and quality assurance capabilities are different. Then, the quality of the final product is certainly different. For example, manual assembly and fully automatic machine assembly, relatively speaking, the quality of manual assembly will be a little higher, but the cost is also higher. So, while choosing a product, you should also know the qualifications that the manufacturer has, and try to choose a manufacturer with reliable and guaranteed quality.
6. Housing material
The housing material of a better tact switch on the market usually uses PC, PP, and LCP materials. Their advantages of heat resistance, impact resistance, and high strength meet the needs of tact switches. Some manufacturers use nylon material in the base to reduce costs, which will greatly reduce the heat resistance of the tact switch and reduce its service life.
Zhejiang Kangerle Electronics Co., Ltd. was founded in 1993 and has been committed to the development, manufacture, and production of electronic switches. Long-term stable and reliable product quality, deeply trusted by customers.
Post time: May-09-2022