In this article, we’re going to focus on using common bipolar junction transistors instead of relays ... more than sufficient in this case. Most NPN-type BJTs will work fine though.

Bipolar Junction Transistors (BJTs) and Field Effect Transistors (FETs). BJTs are controlled by current, while FETs are controlled by voltage. Within these categories, there are further subdivisions ...

Also called a "bipolar junction transistor" (BJT), it is one of two major transistor categories; the other is "field-effect transistor" (FET). Although the first transistor was bipolar and the ...