Snap action switches for precise, repeatable control

A snap action switch uses an over-center mechanism that moves from one electrical state to the other almost instantly at a precise set point, rather than creeping gradually. In Nason designs, the sensing element’s controlled travel produces crisp contact change and repeatable switching suitable for industrial automation.

Pressure and vacuum models use either an elastomer diaphragm or a sealed piston to drive the snap mechanism. Contacts stay open or closed until the exact set point is reached, then snap to the other state and remain there until the differential is crossed in the opposite direction. Temperature models work the same way as limit sensors, opening or closing when the defined temperature set point is reached.

Choose a diaphragm when you need sensitivity and stability at low to medium pressures, especially in pneumatic systems and clean media. Select a piston for higher pressures and rugged hydraulic service where a sealed, wear-resistant sensor is preferred. Nason’s high-pressure families typically use sealed pistons, while many low-pressure families use long-life elastomer diaphragms.

Nason pressure switches span approximately 2 to 7,500 psi across low-, mid-, and high-pressure families, with model-specific tolerances. Vacuum switches cover roughly 1 to 28 inches Hg depending on model and whether the unit is fixed or adjustable. Temperature switches include models with factory-set points across common industrial ranges. Confirm the exact range on the product page or catalog sheet for your chosen series.

Deadband, also called differential, is the separation between the actuation and reset points. It prevents chattering in systems with pressure or temperature ripple. Choose narrower differentials for tight control in stable systems and wider differentials when shock, pulsation, or noise is present.

Both are available. Nason offers field-adjustable options in several pressure and vacuum families and factory-preset versions when you prefer tamper resistance or a validated setting from the factory. The catalog and product pages identify which series are adjustable versus fixed, along with the available adjustment ranges.

Common contact forms include SPDT and SPST normally open or normally closed. Connection options include wire leads, spade quick connects, DIN 43650A, M12, Deutsch, Metri-Pack, Weather Pack, and 1/2 in. conduit entries, among others. The Electrical Options guide shows the full menu, pin assignments, and typical IP ratings by connector.

Nason transducer models are available with accuracy ranges of ±1%, ±0.4% and ±0.25%.

Inventory-reducing build practices keep lead times short. Samples can usually be assembled and shipped quickly, but please consult the factory for exact lead times.