Profile: Pacer International Ltd specializes in optoelectronic, display and laser solutions. We offer a wide range of opto components, sensors, detectors, laser components & systems, information displays, optics & acousto optics, cameras and spectrometers. Solid-state relays (SSRs) are fully electronic devices that offer a compact, high-speed, low-power and high-reliability alternative to conventional electromechanical relays. With no moving parts, reliability is inherently greater than electromechanical relays & their clean, bounceless and silent operation makes them particularly suitable for applications where switching must be performed without audible noise and with no danger of generating sparks. Various different designs are available, including photocoupled SSRs, transformer-coupled SSRs, and hybrid SSRs. Photocoupled SSRs use a controlling LED to trigger a photosensitive diode that operates a thyristor, silicon controlled rectifier or MOSFET to switch the load. Devices are available with single switching elements for DC loads, or with back-to-back switches for controlling AC loads.