Phototransistors are devices that are light-sensitive and are a combination of photodiode-amplifier. They are solid-state light detectors with internal gain that are made use of to provide analog or digital output signals. The SD5410 series phototransistors are used in a variety of applications like printers, copiers, metering, data storage systems, liquid-level sensing, automated transactions, drop sensors, and other medical equipment's.

SD5410-003 Phototransistor from Honeywell features NPN silicon photodarlington mounted in a TO-46 metal package with glass lensed can, providing a narrow acceptance angle. This phototransistor comes with a choice of flat window or lensed package and has a wide operating temperature range of -55 °C to 125 °C. It also comes with wide sensitivity ranges and an option of 90 ° or 12 ° acceptance angle.