Switches
DIP switches: Decades-old technology still ideally suited for today’s applications
By Ryan Smoot, CUI Devices S
ince the 1970’s, DIP switches have been one of the forefront electromechanical devices used by users to make manual changes on any electronic circuit. The straightforward simplicity, low cost, and ease-of-use with DIP switches has seen their usage proliferate in a variety of different electronics applications. Despite their simplicity, they are available in a variety of different styles - switching mechanisms, number of positions, power ratings, sizes, and operating configurations. Due to the way they are used, DIP switches tend to offer more variety in positions offered and they also offer a greater variety of actuation types, either by hand or with a special tool.
How does a DIP switch work? A DIP switch is a dual in-line package switch, basically referring to the fact that there are multiple switches in a single package. Each switch in the package independently activates or deactivates an electronic circuit. As DIP switches are electromechanical devices that are manually moved by a user, they are ideal for applications that require users to configure an electronic device to a specific mode or setting.
Due to their simplistic nature, DIP switches usually only offer one of three different combinations of poles and throws. Often misunderstood, the basics of poles and throws must be covered to truly understand which DIP switch will work best in an application. A single pole, single throw (SPST) switch is the simplest of switches and offers only an open/ close functionality, where an open switch interrupts the current flow while a closed switch allows current flow.
A single pole, double throw (SPDT) switch adds another route for the electricity to flow, where the actuation of the switch does not just open one path but closes another. Thus, the switch not only interrupts the current flow on one circuit branch but allows current flow on another circuit branch.
The final of the three most common switch configurations, the double pole, double throw
44 April 2022
(DPDT) switches could be thought of as two SPDT switches that are controlled by a single actuator. With one actuator, two poles change between two options. Other options for switches tend to simply be an increase in the number of poles or throws, and following a naming convention where the number of poles or switches replaces the letters ‘S’ or ‘D’, such as 3P6T for a 3 pole, 6 throw option.
Again, most DIP switches offer the simpler SPST or SPDT options and have several of them in the same package. As DIP switches are often integrated into embedded devices or other products that work in binary, it is common to see eight position options, as that corresponds to one byte of data, or 256 binary options.
Types of DIP switches Most of the SPST, SPDT, or DPDT electromechanical portions are hidden from view and irrelevant to the end user. However, DIP switches have several different interface types, from piano actuators, slide actuators, rotary actuators, and more.
Slide DIP switches can be used as toggle switches. Each switch has two positions, 1 or 0, closed or open, on or off, which corresponds to the SPST type. SP3T slide switches are also available, where there’s not only two on options but also a central neutral location. These are generally configured in a circuit as on/off/on. Any DIP switch can either be normally open (NO) or normally closed (NC).
Piano DIP switches take the slide DIP switch concept and turn it sideways - instead of forward and back movements on the slide DIP switches, Piano DIP switches have a vertical up and down movement. The only true difference between them is in the user interface of the end product. While the functionality is the same, with a rotary DIP switch, the position is toggled as the user turns the actuator in a circle. There are different distinct options instead of a continuous rotation, usually
Components in Electronics
Figure 1: Example of an 8-Position DIP Switch (Image source: CUI Devices)
Figure 2: Example of a Single Pole, Single Throw (SPST) Switch (Image source: CUI Devices)
Figure 3: Example of a Single Pole, Double Throw (SPDT) Switch (Image source: CUI Devices)
Figure 4: Example of a Double Pole, Double Throw (DPDT) Switch (Image source: CUI Devices)
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