The project described in this article is a ready-made item from a $2.00 shop! And it is made in China! It is a wireless doorbell with a cost of about $10.00. It is so cheap, you could not build it ...

This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now no longer available. The design is simple and sensitivity ...

In this lesson, students build two circuits and explore how transistors function. When Bell Labs introduced the transistor in June of 1948, a spokesman proudly announced "This cylindrical object . . .