In an electric circuit, a switch is a device used to make or break a circuit. This phenomenon, specifically in networking, helps in channeling data from multiple inputs to a specific output.
In an electric circuit, a switch is a device used to make or break a circuit. This phenomenon, specifically in networking, helps in channeling data from multiple inputs to a specific output. The working of a switch can be controlled manually by a human,like switching on a light bulb; by a sensor, as in the case of a thermostat where change in temperature controls the switch; or by another electrical circuit (also known as a relay).
There are many kinds of switches serving a plethora of different purposes, for example, light switch, rotary switch, toggle switch, ,mercury tilt switch, etc. The most common type of switch that we come across every day is electromechanical switch. This switch is made up of a multitude of sets, each of which can be in either of two states: open or close. An ideal switch has absolutely no rise time and fall time when the switch is closed and opened, respectively.
About Membrane Switches
A membrane switch is a printed electronic circuit, in which, pressure is used to open or close the circuit. It is mostly used in devices mostly known as User Interfaces, where the circuit is made up of conductive inks made up of silver, graphite and/or carbon. A membrane switch is essentially a number of thin layers held together using pressure sensitive adhesives. The number of layers depends upon the usage and caries between 4 and 9. As compared to mechanical switches, these switches are easy to clean as they contain no crevices that may trap contaminants, water resistant (meet NEMA 4 and IP 67 specifications) and are easily protected from UV rays.
These also offer the added advantage of lesser price, lesser space, and easy interface with existing controllers and are aesthetically pleasing in appearance, sleeker and ergonomic. There’s an abundance of features that can be added to a membrane switch, like tactile as well as non-tactile feature and lighting options. In the case of lighting, three standard methods are available: Light Emitting Diodes (LEDs), optical fibers and electroluminescent lamps. Membrane switches find their use in many industries like medical instrumentation and laboratory equipment, electronic test and telecommunication networking, etc.
What are touch switches ?
A touch switch, on the other hand, is a type of tactile sensor, albeit the simplest kind. A touchscreen display contains an array of touch switches. A touch switch can be any of the three types: Capacitance switch, resistance touch switch or piezo touch switch. A capacitance switch can function on only one electrode. It is of two types: mutual capacitance configuration and self-capacitance configuration. In the case of mutual capacitance configuration, a sensing capacitor contains two terminals functioning as receiving and emitting diodes.
These are generally preferred for touch screens. The self-capacitance touch switch has one terminal connected to ground. In this configuration, when a person touches the switch, the touch of his finger changes the capacitance. This happens due to the dielectric and conductive nature of the human body. It is generally used for touch sensitive button, wheel or slider.
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