How to Locate Part Numbers for Front Panel Pushbutton and Switches

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Minimizing equipment downtime is a prime consideration for industrial control systems. This is the driving factor for equipment design with roots all the way down to selecting an appropriate pushbutton. This design philosophy calls for a robust switch that can survive harsh environments and a good deal of abuse.

This point cannot be stressed enough. Downtime is extraordinarily costly. Your workforce is idle, no product is produced, and you will likely need to pay overtime to get back on track.

When the switch does break, it is vitally important that the technician(s) troubleshoot and then repair or replace the switch as quickly as possible. In an industrial setting, the technician should have ready access to switch replacement components. Unfortunately, the logistics are daunting.

In this article we will explore a representative family of switches. The lessons learned are generally applicable to all switch assemblies and related industrial components.

Representative Switch

The secret to switch selection is to focus on relationships between families of devices. In this article we will select the EAO Series 04. From within this family, we will down select and focus only on pushbuttons. Representative samples of the Series 04 family are included as Figures 1 and 2.

This may seem like a limited selection, but there are hundreds of thousands of combinations and permutation for pushbutton assemblies within the family. For example, something as unremarkable as the switch elements could include N.O. SPDT or DPDT, N.C. SPDT or DPDT, or combinations of N.O. and N.C. Each switch configuration is available with silver, gold-plated silver, or palladium. That’s 15 unique snap-action configurations so far.

We can also select slow-make switch elements. Most switch configurations are available in both screw-terminal and push-in blade configuration. Finally, the switches may be stacked. The possibilities are endless. So too are the logistical difficulties in finding the exact components you require.

Figure 1: Picture of an illuminated pushbutton assembly manufactured by EAO.

Figure 2: Expanded view of the EAO pushbutton components (missing the LED).


DigiKey offers an extensive line of industrial control switches including the EAO Series 04 components. Many of these devices are in stock ready for immediate shipment. For example, if you need a slow-make DPST (1 N.C / 1 N.O.) switch featuring gold-plated silver contacts with push-in terminals. DigiKey has 10 each of this part number 704.917.5 in stock at the time of this writing.

If you have the specific part number in hand, it’s easy to use DigiKey’s search engine. If you don’t have a part number, are looking for an in-kind replacement, or in the market for a new switch, you will need to augment DigiKey’s search engine with alternative sources. There are two excellent resources including:

Tech Tip: We are careful to use the word “augment”, as in, “the EAO tools are used to augment the DigiKey tools.” We know that DigiKey’s search engine is optimized to find specific parts. This is a fast and easy to use tool when you know a specific part number. We also know that EAO’s configurator is streamlined to find specific switch configuration. The two tools are linked via EAO’s shopping cart. This has an option to check out – to transfer – the shopping cart to DigiKey. Taken together, this provides an excellent method of quickly locating and then purchasing the desired switch components.


Perhaps in the future we can explore additional aspects associated with the “simple” pushbutton. For example, what applications call for a palladium switch? Until then, I trust you can leverage the synergy between the DigiKey tools and online tools to quickly locate your desired components. Be sure to look for similar relationship with other component families and manufacturers.

Best Wishes,


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