Scientific apparatus and instruments for research, measurement, signaling, detection, testing, inspection, and control; apparatus and instruments for the conduction, distribution, transformation, accumulation, regulation, or control of electricity; apparatus for recording, transmission, reproduction, or processing of sounds, images, or data; recorded or downloadable media, software, digital recording and storage media; calculating devices; computers and computer peripherals; alternating current switches; SCR (silicon-controlled rectifier) activated inverters and BCT (bidirectional controlled thyristors) for multiple converter excitation and high-precision alternating current valves. Featuring microprocessor-based static var controllers and high-voltage semiconductor arrays of series-connected thyristors designed for air-cooled, pressure contact connections, arranged in stacks for full-wave power control. Modular, maintainable units with integral ultra-low inductance snubbers and optically triggered thyristors, ideal for controlling high-voltage AC loads such as static var compensator harmonic filters. Incorporating advanced control technology with dedicated I/O systems, real-time clocks, and industrial communication capabilities including EGD (Global Data), Modbus TCP, CIP (Control IP), Profibus-DP, Profinet, DeviceNet, and ControlNet.