Elektingel (programmierbare melodische Tuerklingel)

The E300 and E310 are well-known types of JFET, which have often been used in Elektor projects. Recently however, these two old `workhorses` have been withdrawn by the manufac-turers, and replaced by two new equi-valents which have the same number, but prefixed by a different letter -1300 and J310. The two new types can be used wherever the E300 and E3 l O were specified previously. Fair enough, why all the fuss then? Unfor-tunately there is a slight snag, due to the fact that the J300 and J3 l O are housed in a different type of package.