A Miniature DC switch Based on Liquid Metal Droplets

For existing mechanical circuit switches, the problems of reliability and low cycle life resulting from solid-solid contacts such as Holm force, arc erosion and mechanical wearing remain to be solved. To address these issues, a nontoxic liquid metal (LM) alloy Galinstan is applied as active materials to realize switching via a liquid-liquid contact. We demonstrate a new method to fabricate a miniature DC switching device by encapsulating two LM droplets in a silicon elastomer Polydimethylsiloxane (PDMS) body with designed cavities. By manually pressing and releasing, microsecond level interruption can be realized in a low power DC circuit. Moreover, the high transparence of PDMS helps to visualize the interruption process and diagnose. With simple operations and fabrication process, the switch has a great potential to be applied in a wide range of electrical power switching.