Design and development of light touch switch
A travel switch, also known as a limit switch, can be installed on a relatively stationary object (such as a fixed frame, a door frame, etc., for short) or on a moving object (such as a driving or door for short animals). When the animal approaches the still object, the contact of the connecting rod drive switch of the switch causes the closed contact point or the broken contact to close. The operation of the circuit and the mechanism is controlled by the change of the opening and closing state of the switch contacts.

The light touch switch is an electronic switch, and the switch can be switched on gently when using the switch button. When the hand is loosed, the switch is broken and its internal structure is connected by the force of the metal projectile.

Light touch switch is widely used in household appliances, such as video and audio products, digital products, remote control, communication products, household appliances, security products, toys, computer products, fitness equipment, medical equipment, checking pen, laser pen key and so on. But the touch switch also has its shortcomings. Frequent press will cause the elasticity of metal shrapnel to lose elasticity. Therefore, most of the electrical buttons are directly replaced by conductive rubber or switchgear metal shrapnel, such as computer keyboards, remote controls, etc.

Working principle of light touch switch

The 220V alternating current passes through the bulb H and the rectifier bridge, and becomes a DC pulsating voltage, which is used as a positive bias voltage and added to the thyristor VS and R branches. Daytime: when the luminance is greater than a certain degree, the photosensitive diode D presents a bottom resistance state less than 1K Omega, which makes the triode V cut-off, and its emission is no current. The unidirectional thyristor VS is blocked by no triggering current. At this time, the current flowing through the bulb H is less than 2.2mA, and the bulb H can not emit light. The resistance R1 and the voltage regulator diode DW make the bias voltage of the transistor V not exceed 6.8V, and protect the triode. At night: when the luminance is less than a certain degree, the photosensitive diode D presents a high resistance state more than 100K Omega, which makes the transistor V forward, and the emission is about 0.8V voltage, which makes the thyristor VS triggering and the light bulb H light. RP is the brightness selector for switching in the morning or evening.

Micro switch - touch switch. Structure: the switch panel and the convex button connected to the switch panel are characterized in that the button is connected to the panel by an arc connecting bar on both sides. The button, the connecting bar, and the panel are injected into an integral part, and the button is preferred with a decorative cover. The arc connecting bar of the utility model has a certain elasticity because of its own fine strip, so when the central button is pressed and released again, the elastic effect of the arc connection bar will be reset, so it is not necessary to set the reset spring under the button, at the same time, this kind of structure can be realized by a simple injection molding. This is greatly convenient for manufacturing and assembly. Close switch working principle classification: proximity switch working principle: inductive proximity switch operating principle, inductive proximity switch belongs to a position sensor with switching output, which is composed of LC high frequency oscillator and amplification processing circuit, making use of metal objects when approaching the oscillating induction head that can produce electromagnetic field. Eddy current is produced inside the object. This swirl counteracts the proximity switch, which reduces the oscillation capacity of the close switch, changes the parameters of the internal circuit, thus recognizes the proximity of the metal objects, and then controls the pass or break of the switch. The objects that can be detected by proximity switches must be metal objects.

Install and debug
When installing, put the printed printed board in the transparent plastic box and fix it well, and series it with the controlled electric lamp H, and let it face the bright space in front of the sky screen or the house, avoid the direct illumination of the light at night within 3 meters. Debugging should be carried out in the evening, adjust the magnitude of RP resistance, so that the controlled lamp H will be lit at the appropriate brightness.