Light Probe

The TEEMSS Light Probe has two measurement ranges: 0-4000 and 0-125000 Lux. These ranges are reported by the probe simultaneously to both the fast 10-bit and slow 24-bit input channels of the probe port. The sensor is a silicon photodiode with an integral near-IR blocking filter. This sensor gives the light probe a response mainly in the visible and as such it can is designed for measuring illumination or photosynthetically active radiation used by plants (PAR).

TEEMSS Light Probe

Operation:

The Hamamatsu S1087 photodiode responds most strongly at 550 nm. The probe circuit uses a dual op-amp, the Texas Instruments TCL27L7BCP. The first stage is set in a current-to-voltage configuration and feeds into channel 0 of both the 10 and 24 bit inputs of the probe port. The second stage has a voltage gain of 31 and is fed into channel 1 of both the 10 and 24 bit inputs of the probe port.

Hamamatsu Catalog with S1087 Photodiode (4 MB file).