Using 2n2222 to switch relay on/off with 3.3v

I remember covering H parameters many many years ago.

HFE, hfe, hre, hie, hoe, . . . what a wonderful time back then :nerd_face: .

http://dept.ru.ac.bd/apee/sites/default/files/principles%20of%20electronics%20ch-24%20h%20paratmetes.pdf