BPW21 Photodiode

The BPW21 Photodiode is a silicon photodiode with peak sensitivity at 550nm to 565nm — the green and yellow-green portion of the visible light spectrum that coincides with the peak sensitivity of the human eye – making it the right photodiode choice for photometric light measurement applications where the goal is to measure light intensity as the human eye perceives it, rather than total optical power across the full spectrum. This peak wavelength distinguishes the bpw21 photodiode from the BPW34 whose 1100nm peak is optimized for near-infrared sensing.

The bpw21 photodiode is sensitive to the visible green-yellow light range that ambient light meters, lux sensors, and colorimetry instruments are designed to measure, making it well-suited for visible light intensity projects. The photodiode bpw21 is a bare 2-pin silicon photodiode in a through-hole package that generates a photocurrent proportional to the intensity of visible light falling on its active surface.

Requiring an external transimpedance amplifier (op-amp current-to-voltage converter circuit) to convert the small photocurrent into a voltage readable by an Arduino or ESP32 ADC pin, the same circuit approach as other discrete photodiodes. The 2-pin through-hole mount allows the bpw21 silicon photodiode to be inserted directly into a standard breadboard or soldered onto a PCB without adapters or special mounting hardware. Available on StemVolt. This photodiode sensor is ideal for lux meter ambient light photometry colorimetry and project visible light photodiode.

Related Products:

• Explore Light, Colour and Camera Sensors

Features:

• 550-565nm peak matches human eye green-yellow visible light sensitivity
• Photometric sensing measures visible light as human eye perceives it
• Different from BPW34 visible optimized vs BPW34 near-IR 1100nm peak
• 2-pin through-hole direct breadboard and PCB insertion no adapter
• Silicon photodiode stable linear photocurrent response across visible spectrum

Technical Specifications:

Applications:

• Arduino lux meter measuring visible ambient light with bpw21 photodiode
• Builds colorimetry sensor using bpw21 silicon photodiode green peak
• Project for photodiode bpw21 visible light photometry circuit demo
• Ambient light level monitor using photodiode sensor 550nm green sensitivity
• bpw21 photodiode pinout for transimpedance amplifier visible sensing

Package Include:

• 1 x BPW21 Photodiode