1. The 4N33 is an optoisolator manufactured by Vishay. It is a six-pin phototransistor output optocoupler with a GaAs infrared LED.
2. It features a UL recognized Insulation materials class F or B, as well as a creepage distance of 7 mm between pins.
3. It also has high isolation voltage (=5 kVrms) and no minimum operating temperature.
4. As with most optocouplers, it has an opacity of 2.5 mm and can handle high current (up to 50 mA). It can also operate over a wide temperature range, from -25 to +85 degrees Celsius.