Notes on Mechanical Devices for the Electronics Experimenter

Summary

I got this book because I don't know much about mechanical engineering and this seemed like a great intro.

The introduction says it's meant for amateur experimenters to get a good foundation for experimentation and measurement and build by designing<=>building<=>testing.

Perfect!

Ch 1: Basic mechanical principles

Fundamental Qualities

We need to define some fundamentals before getting to the interesting stuff. Let's power through it.

There's 3 fundamental qualities that makes up reality, physics-wise:

1. Length - was once defined by a metal rod. Now it's defined by the speed of light.

2. Time - Once defined by a fraction of a day in 1900. Now it's defined by periods of radiation from a cesium atom.

3. Mass/Weight - Mass is constant, but weight is "mass * the-acceleration-of-gravity". In any case, for us it's the same.

Notably, here's a few units of mass:

• kilogram - kg -- 2.204 pound-mass
• pound-mass - lbm -- 0.4536 kg
• slug - slug -- 32.174 pound-mass

Yes, we're just treating pounds as a mass by calling it pound-mass.

There's also these other relevant units of reality:

• Electric Current - force generated between two conductors at some length, measured in "ampere"
• Luminous Intensity - light-ness, measured in "candela"
• Temperature - measured in "kelvin" as well as F and C.

Vectors & Motion

How do measure how stuff moves across space (length) and time?

Vectors

Vectors show you force has a horizontal and vertical component. For example, if this slash "\" had an arrow pointing down, then if it were moving a box, that would push it both into the floor and across the floor. Woo hoo.

Motion

Here's some key things:

1. Speed / Velocity - distance over time

2. Rotational Speed - revolutions per minute or angular distance traveled (degrees per second, radians per minute)

3. Acceleration - the rate of change of velocity. So if acceleration is 0, then the velocity is constant. (d*sec^-2)