Choosing the best electronic switch for an application requires knowing what kind of load it can handle, how long the switch will be operative, what regulations it meets, and the kind of environment it can function in. Another way to choose a switch is to see the type of rating given by Underwriters Laboratories (UL), or the level of Ingress Protection (IP) specified by the International Electrotechnical Commission (IEC). Electronic switches mount to circuit boards in different ways, including surface mounts, soldering, or with a quick connect design. Some might not be able to handle the temperatures of soldering, while the size needed affects the choice because so many components must fit onto small circuit boards of even home electronics.
An electronic switch must be able to handle the load and voltage of the particular device it is being used on. If it is rated too low, then the power of the device can short it out and the switch won’t work. Too high a rating could make a switch inefficient and unnecessarily expensive. The functions of mechanical contacts are not relevant because electronic switches contain bipolar junction transistors or field-effect transistors. One must know the ratings of these components, which are usually listed in the product’s specifications.
Life expectancy is another concern. Depending on the quality, a switch might be less expensive but cost more later on to maintain and replace, especially if it is mounted to a circuit board. An electronic switch may also need to operate in the presence of moisture, high temperatures, or dust depending on where it used. Building electronics are usually placed in a controlled environment, but electronic switches used for industrial systems, medical devices, and construction equipment are often exposed to the elements.
The IP ratings of the switch indicate how protected it is. An IP 65 rating, for example, means that the electronic switch can be used where there is dust in the air, and where there is direct exposure to water. If it is IP 67 rated, the switch can be immersed in water, while lower ratings such as IP 60 mean exposure to water would damage the device, but that dirt won’t get inside. All of the IP ratings specify how well any electronic enclosure is sealed. The size of the electronic switch is also important, because whether it is a standard, miniature, or ultra-miniature switch affects inclusion into the overall design of the electronics.
