稳定光源可持续输出一定功率的稳定光，主要用于调节光电倍增管及光电倍增管模组的灵敏度，可以直接用于探测器产品的校准、产品检验等用途，也可以用于传递溯源。 DL20A系列稳定光源基于单波长LED，产品内部包含光源模块及光源控制电路，可驱动其输出稳定波长的光。输出波长可选，功率包含强弱档。本系列产品为黑色的金属盒式，由2节AAA电池供电，体积小、易安装，具有可靠性高、不易损坏、单次电池使用寿命长等优点。

The DL20A series are LED light sources mainly designed for adjusting the sensitivity of PMT(photomultiplier tubes)and PMT modules. The DL20A series is a plate type designed to be placed on a sample stage. Stable continuous light of approximately 1 pW is always output because the LED emission power is controlled by monitoring with a photodiode. Two models are available: DL20A-430 and DL20A-570.