What this slot phototransistor does in a board-level circuit
The RPI-441C1E is a through-hole slot-type phototransistor from ROHM Semiconductor, part of the RPI-441 series. It is an unamplified sensor — the transistor output switches directly when an object breaks the 0.157 mm sensing gap, making it a simple, low-component-count solution for position or edge detection in a PCB assembly. Rated for a supply voltage up to 30 V and a switching current of 50 mA, this sensor can drive a logic input or a small relay directly without an external transistor stage. The 10 ms response time is adequate for detecting moving parts at moderate speeds — think a flag on a conveyor or a cam in a rotary encoder.
Temperature grade and deployment context
Rated for an operating temperature range of -25°C to 85°C, this sensor fits indoor industrial and commercial equipment — control panels, printers, vending machines, and lab instruments. It is not specified for extended automotive or outdoor temperature extremes.