SPST (Single Pole Single Throw) pressure switches are available with Normally Open (N.O.) or Normally Closed (N.C.) contacts.

Their operating principle is based on the balance between the fluid pressure acting on the sensing element and the force exerted by a calibrated spring. When the preset switching pressure is reached, the device changes the state of the electrical contact, generating the signal required by the control system.

In the N.O. configuration, the contact closes when the pressure threshold is reached; in the N.C. configuration, the contact opens when the same threshold is reached.

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