Transistor chip photos

These photos are of power transistors with the lids filed off. The top transistor had too much current and the emitter wire melted off the chip, leaving a mess on the silicon chip. The base wire is still there. This transistor has a complex metalization pattern at the white arrow, which is the little input transistor of a Darlington.

On both chips, the emitter and base metal is interdigitated, and the collector current flows through the chip, vertically, to the metal can. These transistors would be $4 currently, seeing as how they are high-power, metal packages. These chips in plastic packages would be $1.

Integrated-circuit chips are much more interesting than these simple transistor chips, but they are too small to photograph with just a magnifier.

Until 1957, all electronic devices used vacuum tubes, and you could look at the parts of the tube, read about the parts, and understand how they amplified. With transistors, the "works" are below the suface of the silicon chip and you can only see the metal on the surface. The physics of how transistors work is a graduate-level topic, so do-it-yourselfers have to be content with knowing what they do, not how they work. Since transistors are as cheap as $.025, we can make neat, even complex, circuits that do useful things, cheaply, so who cares that we don't know much about how transistors really work.