Sometimes manufacturers refer to industry standards in their datasheets or drawings without explaining them, which can be confusing for those new to switches.
One such standard involves the use of parentheses around switch actions. For example, the manufacturer part number PA412C1100 (DigiKey part number EG4688-ND) includes a part builder in its datasheet that breaks down the part number:
- PA4 is the series
- 1 indicates 4.8mm tabs
- 2 means it’s a 2-pole switch with an Off-On function
Now, if you were to replace the “2” with an “E”, the datasheet shows Off-(On) – but doesn’t explain what that means.
Here’s the key: When a switch action is shown in parentheses, it indicates a momentary function.
So Off-(On) means the switch returns to Off when released – a momentary On. In contrast, Off-On means the switch toggles and stays in the On position until pressed again. This means that PA412C1100 is a non-momentary toggle switch. Understanding this notation will help comparing or selecting other variants.