Key switch refers to the use of a button to push the transmission mechanism, so that the moving contact and the static contact are pressed together or A switch that opens and ends a circuit changeover. The key switch is a simple and widely used master electrical appliance. In electrical active control circuits, it is used to manually announce control signals to control contactors, relays, electromagnetic starters, etc. The key switch can complete basic controls such as start, intermittent, forward and reverse, speed change and interlock. Generally, each key switch has two pairs of contacts. Each pair of contacts consists of a normally open contact and a normally closed contact. When the button is pressed, the two pairs of contacts act together, the normally closed contact is disconnected, and the normally open contact is closed.
Key switchThe AC power input is rectified and filtered into DC; the switch tube is controlled by a high-frequency PWM (pulse width modulation) signal, and the DC It is added to the primary of the switching transformer; the secondary of the switching transformer induces a high-frequency voltage, which is rectified and filtered to supply the load; some of the output is fed back to the control circuit through a certain circuit to achieve the purpose of stable output. The key switch is a relatively complex layout. A kind of switch, its constituent parts include handle, slide plate, contact piece, terminal, spring and so on. The operation of the key switch is transmitted from the key to the handle, and the handle then controls the contacts and terminals, ending the opening and closing control of the contacts. Key switches can be divided into single-button button switches and multi-button combination button switches. There are two types of key switches: single key type and multi-key combination type. The single-button key switch is generally used as a power switch in a TV set, and it is divided into a self-locking and self-resetting type (this switch is pressed once to turn on self-locking, and then pressed again to disconnect and reset) and a non-locking type (no lock). Confirm, switch on when pressed, reset when released) two layouts. Toggle Switches Multi-key combination key switches are classified into self-locking, interlocking and non-locking layout types.
Material selection of key switches, the materials used in key switches and toggle switches, in terms of flame retardancy, insulation, impact resistance And moisture resistance and other aspects are very excellent, the material stability is strong, not easy to change color. In addition to high-grade plastics, button switches also have metal materials such as gold-plated, stainless steel, and copper, providing us with more and more choices.
