IR RX LED (BLACK)

PT-333-3B IR RX LED (BLACK)
Unlike an IR LED that emits light, this photodiode acts like a light-sensitive valve. It is typically used in a Reverse Bias configuration. In total darkness, it blocks electricity (Dark Current); however, when infrared light hits its silicon surface, it generates electron-hole pairs that allow current to flow through the circuit.

Why it’s a Robotics & Sensing Essential:
• High-Speed Response: Because it lacks the processing delay of a demodulator, it can react to changes in light in nanoseconds. This is critical for high-speed line-following robots or object counters on fast-moving conveyor belts.
• Broad Spectral Sensitivity: Its sensitivity peak is centered around 940nm, making it perfectly matched with most standard IR LEDs used in hobbyist electronics.
• Flame Detection: Since fire naturally emits a massive amount of infrared radiation, the PT-333-3B is frequently used as a flame sensor to detect the "flicker" of a fire from a distance.
• Compact 5mm Package: It shares the same form factor as a standard LED, allowing it to be mounted easily on PCBs or inside 3D-printed brackets alongside an IR transmitter.

Technical Capabilities:
• Spectral Range: 700nm to 1050nm (visible red to near-infrared).
• Light Current (I_L): >= 3mA (The amount of current it allows through when fully illuminated).
• Low Dark Current (I_D): < 0.1muA (Ensures almost zero "noise" when no IR light is present).
• Durability: Operates in extreme temperatures ranging from -40°C to +100°C.

Best For:
The PT-333-3B is the primary choice for custom proximity sensors, optical tachometers (measuring RPM), firefighting robot eyes, and automated hand-sanitizer dispensers.