The 4N25 family is an industry-standard single channel phototransistor coupler. This family includes the 4N25, 4N26, 4N27, 4N28. Each optocoupler consists of a gallium arsenide infrared LED and a silicon NPN phototransistor.
• AC mains detection
• Reed relay driving
• Switch mode power supply feedback
• Telephone ring detection
• Logic ground isolation
• Logic coupling with high-frequency noise rejection