4-Channel Isolated Voltage Interface Module

This isolation interface module integrates four PC817 optocouplers to deliver safe, bidirectionally isolated signal translation between low-voltage control domains and higher-voltage load circuits. Board dimensions: 53 mm × 27 mm × 15 mm; typical weight: 12 g. Control input accepts 3.3 V or 5 V logic signals (functional from 3.6 V to 24 V); isolated outputs support 3.6 V to 30 V loads. Per-channel maximum current: 10 mA; power delivery follows inverse V–I relationship to maintain constant total output power. Terminals are screw-type for secure, tool-free connection on both sides. Material: FR-4 PCB with tin-plated copper traces and standard through-hole optocoupler mounting. Operation is straightforward: energising any control input turns on its paired output, allowing direct switching of relays, gate drivers, or indicator circuits. The module does not invert logic — high on input yields high on output. Suitable for permanent installation in control cabinets, test jigs, or edge-computing nodes where EMI resilience and fault containment are design priorities. Used widely in education labs for teaching isolation principles, in prototype automation rigs for validating sensor–actuator chains, and in retrofitting older equipment with modern microcontroller brains — all while preserving original 24 V I/O infrastructure and meeting basic functional safety expectations.