Barter is the present and the future of international trade, especially for people who is starting in the import export business. Barter and more: Triangular operations.
Common classification of keyboards
There are two types of conventional keyboards: mechanical keys and capacitive keys. In the industrial computer keyboard, there is also a keyboard with a light touch membrane key. The mechanical keyboard is the earliest structure adopted. Generally, it is similar to the principle of a contact switch to make the contacts turn on or off. It has the characteristics of simple process, convenient maintenance, general hand feeling, high noise and easy wear and tear. Most of the cheap mechanical keyboards The copper sheet spring is used as the elastic material, the copper sheet is easy to fold and lose its elasticity, and the failure rate increases over a long period of use, and the capacitive keyboard is It is a keyboard based on capacitive switches. The principle is to change the distance between the electrodes by pressing the keys to change the capacitance, and temporarily form the conditions for the oscillating pulse to pass through. In theory, this switch is non-contact and non-contact, the wear rate is very small or even negligible, and there is no hidden danger of poor contact. It has low noise, easy to control the feel, and can produce high-quality keyboards, but the process is more mechanical. complex structure. There is also a keyboard for industrial computers that uses light-touch membrane keys in order to be completely sealed, which is only suitable for special occasions.