Here’s a simple FET circuit that lets you switch power ... Unlike with BJT transistors that need a constant current flow, you only need to charge a gate once for the FET to remain open for ...

But from there he moves on to the juicy bits. He builds a transistor-based constant current driver, then adds voltage regulation for the circuit as seen in the schematic on the left. He moves on ...

Many people giving talks had complained about the current germanium transistors ... outcome of being part of an electrical circuit -- the transistor would have too many free electrons.