Litemeter Current PAR

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Litemeter Current PAR is an silicon pyranometer with a filter for Photosynthetically Active Radiation (PAR) – the wavelength of light plants use in photosynthesis. It can be used outdoors, in greenhouses, in water or in growth chambers. Ideal for use in floriculture, agriculture and biology.

There are similarities between the photovoltaic phenomenon and the ‘light-dependent reaction’ of photosynthesis. The Sun is the primary energy source. Electrons jump in the upper atmosphere when hit by the Sun’s rays.

PAR graph - spectral irradiance used by plants in photosynthesis

Thanks to a dedicated filter, a PAR meter measures the spectral portion of the light in the 400-700nm range along a planar surface which corresponds to the PAR (Photosynthetically Active Radiation). This is the precise wavelength on which plants photosynthesize.

The measure of PAR along a flat surface is called PPFD or PARMETER in experimental growth chamber for algae “Photosynthetic Photon Flux Density”. It differs from “Photosynthetic Photon Flux Fluence Rate” (PPFFR) which is revealed by spherical sensors of PAR.

PAR sensor monitoring algae

Litemeter Current PAR measures PPFD. It can be used outdoors, in greenhouses, in water or in growth chambers.

Output is in current loop and values can be easily converted in µmol of photons per square meter per second (µmol /(m2 * s) ) S.I. Units

In terms of precision to price, Litemeter Current PAR offers great value.


Calibrated for comparison with our silicon reference cell calibrated periodically by the Fraunhofer ISE Institute in Germany, and a multimeter HP34410A with over 0.2% accuracy.

Most common uses

Detecting electromagnetic radiation in photosynthetic wavelengths (400-700nm) is useful for monitoring research and economic production activities where biological growth is important. For example:

  • Intensive agriculture
  • Floriculture
  • Fruit growing
  • Algal growth
  • Aquariums
  • Marine biodiversity studies

Note: A PAR (Photosynthetically Active Radiation) Sensor measures photosynthetic light levels in both air and water. The sensor responds to visible light in the spectral range that is used by plants in photosynthesis (400–700 nm). PAR meters are used widely in agriculture and environmental studies.


PRODUCT LM1-420PAR – analog silicon pyranometer with a filter for PAR
REFERENCE STANDARD IEC 60904-2; 60904-4; 60904-10; Li-190R
Input range Irradiance 0 – 1300 W/m2
Spectral range 0.36 – 1.14um
Output Voltage 4V – 30V DC temperature compensated
Output precision Irradiance ±4% annual average
Sensor type photovoltaic silicon with Passband filter
Power supply External, 8-30V dc
Encapsulant Aluminum with a screw clamp for fixing on the modules or on the mounting profile to their same inclination and orientation.
Cable 60cm or 3m UV and high temperature resistant.
Connector (*) Version with standard M8 4-pin connector or without connector(2+1 pin)
Dimensions 48x62x15mm
IP grade IP67

(*): Note: see order code.


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