Waterproof tact switch is a functional electronic switch. When in use, the switch can be turned on by simply pressing the switch button. The internal structure of the switch is turned on and off by metal springs; the watertight tact switch Due to the low contact resistance, the obvious degree of crispness when pressed, and the complete range of height specifications, the waterproof tact switch applications and package specifications are diverse, especially in household appliances. How to detect waterproof Tactile switches are important to the principle of waterproof tactile switches. The following editor will explain the working principle of waterproof tact switch for everyone.
The working principle of the waterproof tact switch: For example: After 220V AC power passes the bulb H and the rectified full bridge, it becomes a DC pulsating voltage, which is applied as a forward bias to the thyristor VS and R branches.
1. When the brightness at night is less than a certain degree, the photodiode D is in a high-impedance state ≥100KΩ, so that the triode V is turned on in the forward direction, and the emitter has a voltage of about 0.8V, so that the thyristor VS is triggered to be turned on, and the bulb H emits light.
2. When the daytime brightness is greater than a certain degree, the photodiode D exhibits a bottom resistance state ≤1KΩ, so that the transistor V is cut off, and its emitter has no current output, and the unidirectional thyristor VS is blocked because there is no trigger current. At this time, the current flowing through the bulb H is less than or equal to 2.2 mA, and the bulb H cannot emit light. Resistor R1 and zener diode DW make the triode V bias voltage not exceed 6.8V, which can protect the triode. RP is a brightness selection element that achieves switching in the morning or evening.
The process of waterproof touch switch: stamping-injection-cleaning-assembly-molding-inspection, the color is relatively single, because the waterproof touch switch has high requirements for the production environment, so the higher the dustproof level The more secure the production is in the workshop. In addition, the cost and price of waterproof tact switches are relatively low, and generally do not cause large price adjustments due to market raw material fluctuations.
There is a switch that is very similar to a waterproof tact switch. It is called a membrane switch. The difference between it and a waterproof tact switch is that the membrane switch is a button with its own circuit. Usually the top layer is composed of PET or PC and other materials Or patterned panel, the lower layer is a conductive line, the middle layer is a double-sided tape made of PET material that simulates the switch and acts as an isolation. The lowermost part is usually the contacts and connection lines on the PET material. Membrane switches are easy to use and flexible, and can be customized according to different needs in different colors, sizes and appearances.