OMRON Basic Switches & Selections
Basic Switch Definition
A Basic Switch has a micro contact gap and snap-action mechanism∗, and turns ON and OFF with a specified movement and force.
∗Snap-action Mechanism
This is a mechanism that enables instant switching at a fixed operating position, regardless of the operating speed and operating force of the switch.
Features of Basic Switches
| Compact, High-capacity Switching | Because the contacts switch instantly, any arc between the contacts will not continue for a long period of time, which enables the switching of large currents in a small package. |
| High Accuracy | Switching occurs at nearly the same pushing position every time, which allows for high-accuracy position detection. |
| High Durability | Any arcs between the contacts do not last long, which reduces the damage done to the contacts for greater durability. |
| Responsive | Our snap-action mechanism design produces a unique clicking feel and sound for superb operational responsiveness. |
Basic Switches are designed for detection, but can also be used as manual switches.
Basic Switch Models
Basic Switches come in four sizes: General-purpose, Miniature, Subminiature and Ultra Subminiature, depending on the device and scale of the equipment they are to be used in.
We have also added Sealed Basic Switches to the lineup that are designed to provide environmental resistance
Basic Switches are divided into four size categories: Z, V, S and J.
Z, V, S and J are quoted the marks from NECA classification.
(NECA : Nippon Electric Control Equipment Industries Association)
Basic Switch Structures
Basic Switches consist of five functional sections: actuator, snap-action mechanism, contacts, case and terminals.
Each of these functional sections consists of smaller parts.
The actuator relays the external force and movement to the internal mechanisms.
Many different types of actuators can be attached to the actuator depending on the shape and movement of the detection object, based on a pin plunger.
Select the actuator that is best suited for the shape and movement of the detection object.
Basic Switch Lineup
Z-size General-Purpose Basic Switches
The snap-action operation is performed by a highly conductive spring.
With a snap-action mechanism, the contacts will instantaneously switch at a specific operating position regardless of the operating speed and operating force of the switch.
As opposed to a snap-action mechanism, with a slow-action mechanism, the operating speed of the switch is always the travel speed of the contacts.
If you press down on the top of a sheet of plastic that is bent info an arc, the sheet will suddenly reverse to a U shape at a certain point. This is like a snap-action mechanism.
Features of Snap-action Operation
- Because the contacts switch at high speed, any arc between the contacts will not continue for a long period of time.
- This reduces contact wear and maintains contact reliability.
- Even small sized switches can make and break large currents.
With AC, the current flow alternates, so arcs are cut off more easily at the same voltage and current in comparison with DC.
Therefore, there is less contact damage with AC.
When pressure is applied to the pushbutton of a switch, the force of the movable spring causes the moving contact to quickly switch from the NC fixed contact to the NO fixed contact.
When pressure is released from the pushbutton of a switch, the force of the movable spring causes the moving contact to quickly switch from the NO fixed contact to the NC fixed contact.
The contacts reliably switch electricity to make or break the circuit.
We also offer a variety of shapes and materials for contacts, and different contact gaps depending on application conditions.
Typical Contact Shapes
Crossbar Contacts for Microloads,
Primarily Made of Gold
Rivet Contacts for Medium to High Loads,
Primarily Made of Silver
These contacts have a small contact surface and have high contact pressure per unit area, making them suitable for use with microloads.The primary materials used in these contacts are gold alloy
These contacts are used for a wide range of applications from standard to high loads. The primary materials used in these contacts are bronze, silver plating and silver alloy.
Contact Gap
※The contact gap values are design values.
Select the contact specifications based on the load to switch and application conditions.
The case is highly insulating and mechanically durable to protect the internal mechanisms of the switch.
Cases are normally made of thermoplastic PBT or thermosetting PF.
Typical Case Materials
|
Material Name |
Material Symbol | Features |
| Phenol resin | PF | A thermosetting resin. It provides superior resistance to combustion and tracking. |
| Polybutyrene terephthalate resin | PBT | A thermoplastic resin. A type of this resin that is reinforced with fiberglass is used for basic switches. |
| Polyamide (nylon) resin | PA | A thermoplastic resin. This type of resin has high heat resistance. It slides well and absorbs water well. |
| Polyphenylene sulfide resin | PPS | A thermoplastic resin. I It provides better resistance to heat than PA. It is used when heat resistance is required, e.g., for soldering. |
Materials are divided into two types: thermosetting resins and thermoplastic resins.
Thermosetting Resin: These resins harden when heat is applied to them. They cannot be reused.
Thermoplastic Resin: These resins melt when heat is applied to them. They can be reformed to recycle the materials.
A thermoplastic resin such as PBT is usually used.
The terminals are used to connect to external circuits.
We also offer a wide variety of terminals.
- Bronze alloy is often used in terminals.
- Some terminals use silver plating to increase conductivity. (In some cases, gold plating is used to prevent discoloration due to oxidization and sulfurization.)
- We provide both self-clinching terminals and angle terminals for PCBs.
Each series has its own terminal variations. Select the terminals you need based on your application environment.
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