Source and Load Matching: Cyclist Perspective

If you ever ride a bicycle – you know how amazing that a bicycle with gear allow you to “match” your muscle (energy source) to any landscape (load). Essentially the gear match the source to load just like the way transformer match an AC source to its load.

Let’s look at a simplified diagram of the torque that your leg muscle generate versus the landscape – slope degree.



Assuming that at gear ratio of 1:1, for every turn of pedals the wheel will turn by one cycle, then:

Low Gear (1:0.5) means for every turns you make on the pedals, the wheel only make half a turn, since your leg muscle power is constant, your loss on speed is made up with your increase of forward force.

High Gear (1:2) means for every turns you make on the pedals, the wheel only make 2 turns, since your leg muscle power is constant  your gain on speed is made up with your reduction of forward force.

Now compare this to the impedance matching in audio amplifier:


Picture from Wikipedia - transformer to perform impedance matching

Impedance matching–What does a mountain bicycle has in common with a transformer

As a cyclist and a transformer user, can’t help to notice the similarity of the two. So below is the picture of a mountain-bicycle and transformer taken from my favourite source Wikipedia.


To compare them, look at the table of comparison below:

A Bicycle	A Transformer
number of “teeth” of sprocket	number of winding
front sprocket	primary winding
rear sprocket	secondary winding
gear chain	transformer core

now, isn’t this amazing?


To understand sprocket, visit http://en.wikipedia.org/wiki/Sprocket

Pictures from :

http://en.wikipedia.org/wiki/Bicycle

http://en.wikipedia.org/wiki/Transformer