A snap-action switch and actuator are disclosed in which a resilient columnar compression member is axially loaded to the point of catastrophic buckling. In one embodiment, the column serves as both an electrical conductor and a contact. In this embodiment, it buckles into contact with another conductive member to complete a circuit. Alternatively, the buckled columned may actuate a piezoelectric, optical or other signal producing means to produce signals used for switching or closing contacts.