# lec6

> diagrams needed for this section

## Transistors

Two types of transistors will be discussed here: `NPN` and `PNP`.
Both types however, do share some properties here by referred to as the following:

* E = Emitter
* B = Base
* C = Collector

### NPN

When the base/gate is "on" we mean current can flow from the emitter to the collector.

### PNP 

When the base/gate is "on" we mean current can _not_ flow from the emitter to the collector.

> When we say that a gate is "on" we're really saying that it's open.


