This video discusses the basic principle and operation of a cascode amplifier (common emitter amp followed by a common base amp). The cascode is often used to counteract something called the Miller Effect which is often the dominant cause for limited BW in an common emitter amplifier. The miller effect is presented, followed by a discussion of how the cascode amplifier helps to eliminate the miller effect. NOTE that the base-collector capacitance drawn on my schematics is representing the base-collector junction capacitance of the transistor - it is not an actual component on the board. Measurements are made on a common emitter amp and cascode amp to observe the benefit of using the cascode structure.
The circuit board used in the video was sent to me by Marcus EA5IGC. More about this circuit can be found here:
(original link: http://marcusjenkins.com/amateur-radio-2/a-signal-amplifier-module-for-hf/)
Original link doesn't work, but did find an archive on the wayback machine:
https://web.archive.org/web/20160427125808/http://marcusjenkins.com/amateur-radio-2/a-signal-amplifier-module-for-hf/
A copy of the notes shown in this video can be found here:
http://www.qsl.net/w2aew/youtube/cascodemiller.pdf