Resistance

In electronics a resistor is like a kinked hose.  This may seem like a bad thing but if we follow the hose analogy we can think of some useful applications of this kinky situation.  Say you want to spray someone with water but, even with the spigot completely open, the water only shoots a foot from the end of the hose.  If you half kink the end of the hose you can squirt the same water several meters away and thoroughly soak your intended victim. (This is actually an example of the venturi effect but I’ll have to return to fluid dynamics another time).

An electrical resistor has many uses based on its configuration and design. In one of its simplest applications a resistor acts to slow (or resist – hence the name) electrical flow. In this situation I imagine that the resistor is like a blocked hose in which the pressure builds and causes the hose to swell.  However instead of pressure building up as in the hose, the resisted electron flow results in heat.  I had a kiln that worked in this way. The heating elements were simply coils made of a metal that didn’t allow the electricity to easily flow and the coils got hot.  The same principle can be seen in an electric stove. The glowing red coils are the result of the material resisting the electricity that is trying to flow through it.

Other uses of resistors are to modify the amount of electricity flowing though a circuit.  Here the hose is kinks so that only a small trickle can get through. For example if a power supply is 12 volts but the LED you want to light only needs 3 volts, a resistor is needed to reduce the flow to an acceptable level for the LED.  Without the resistor the 12 volts from the power supply would overload the LED and burn it out.

There are a ton of other forms of resistors and they are ubiquitous in electronics designs.  One cool one that is a bit more nuanced than simply slowing the flow or reducing it is a potentiometer.  A potentiometer is a variable resistor that allows the flow of electrons to be modified through a wide range.  This may sound weird but potentiometers are very commonplace, in fact you can probably see a potentiometer from where you are sitting right now.  So what is it? If you’ve ever said “pot” that music up, you already know an example of a “pot”entiometer.  Volume (and pretty much all other) knobs are examples of potentiometers. 

So to review, the next time your buddy is running this blog through a text recognition program so you can listen to it but the room is too loud, you might consider saying, “hey pot up that blog, I want to hear this!”