Recently, Shibib et al. /1/ and Van Cong et al. /2/ reported a relation that describes the effect of band-gap narrowing (BCN) on the effective electric field experienced by the minority-carrier holes in the n-type heavily doped emitter region of silicon p-n junction solar cells. Accurate models of this effective electric field are important for understanding and improving device performance, not only for solar cells /1 to 3/, but also for other junction devices such as high-accuracy photodetectors /4/. Our previous theory of BGN. /2/ is more applicable to heavily doped materials than to moderately doped semiconductors typically used in devices /3/.The purpose of this note is to investigate the effective electric field E acting on the minority-carrier holes in n-type moderately doped silicon at 300 K, in which the donor concentration range 1s found to be 1 0 2 3 . 5~1 0 which will be referred to as I.