Some basic definitions, equations and analogies of electricity.

## Definitions

Electrical Parameter (symbol) Measuring Unit (symbol) Description Water Analog Elec. Units Base Units
Voltage (V) volt (V) Pressure (Potential) difference due to charge difference. V=I*R Head: Pressure (Potential) difference due to height difference J/C kg•m²/(s³•A)
Current (I) amp (A) Flow of charge in charge/time or coulombs/sec. I=V/R Flow: Flow of water in volume per time such as liters/sec C/s or W/V A
Resistance (R) ohm (Ω) Opposition to the flow of charge. R=V/I Friction: Opposition to the flow of water V/A kg•m²/(s³•A²)
Power (P) watt (W) Rate or work or energy transfer, storage, etc. Power=Energy/Time also P=I*V Power: Power=Flow (Q) * Pressure (H) J/s or A•V kg•m²/s³
Energy (E) watt-hour (Wh) The ability to do work. Often E=P*t (where t is time) Energy: The ability to do work 3600 J kg•m²/s²

## Equations

P=IV
Power=Current*Voltage
look familiar, see P=Q*H*e/k from microhydro power
V=IR
Volts=Current*Resistance
I=V/R might be more edifying since current is usually the result of pressure acting on resistance.
This only applies to ohmic circuits, those circuits which display a linear relationship between current and voltage (i.e. the resistance does not change based upon current or voltage).
Series Parallel
VT=V1+V2+… V stays same
I stays same IT=I1+I2+…
RT=R1+R2+… 1/RT=(1/R1)+(1/R2)+…

## Analogies

The following animated analogy illustrates the operation of direct current (DC) circuits.

Water Tank - Electricity Analogy
Component Analog
Tank Battery
Tank Vertical Difference Battery Voltage Difference
Water Flow Electrical Current
Mechanical Energy Appliance (Blender) Electrical Energy Appliance

• How fast will the battery run out?
• How fast will the virgin margaritas be made?
• And most importantly why?

If you would like to do math to support these analogies, use:

• Feet = volts
• GPM = amps
• Each blender has a resistance of 6 Feet/GPM = 6 ohms

### 1 Tank 1 Blender

• This is the test case (datum).

### 1 Tank 2 Series Blenders

Notice that:

• The flow is 1/2 the speed of our test case.
• The two blenders in series are each going 1/4th the speed of our test case.

### 1 Tank 2 Parallel Blenders

Notice that:

• Each blender is at the same speed as our test case.
• The flow from the tank is twice as fast as our test case.

### 2 Parallel Tanks 1 Blender

Notice that:

• The blender is the same speed as our test case.
• The flow from each tank is half as fast as our test case.

### 2 Series Tanks 1 Blender

Notice that:

• The blender is 4 times the speed as our test case.
• The total flow is twice the speed as our test case.

PS The second tank has a lid that keeps it closed.

## Background Essentials

See Rural Electrification Systems for more background information (these page should be integrated together).

# Discussion

I want to move this page to Lonny's electricity basics, for the following reasons:

1. Dissuade encyclopedic content by moving stuff off of category pages and onto more in-depth pages, such as tools, curricullum/lecture notes, etc.
2. To encourage teacher's to use appropedia as a resource.
3. And a couple of other reasons, but I have to run...

Any comments? Especially about the naming convention, or even the whole idea?

Thank you, --Lonny 09:36, 11 October 2006 (PDT)

My question would be related to categorization. You say "move stuff off category pages", but then it gets harder to find by browsing. That is, it still seems like it should be part of "Topics" or "Curriculum" or similar category. --Curtbeckmann 15:02, 11 October 2006 (PDT)
I meant to move some of the content off of the Category:Topics pages, and replace it with subcategories and articles inside of that Category:Topics. So the page, Electricity basics would be renamed Lonny's electricity basics, which would, in turn, be an article in Category:Electricity, as well as either Category:Curricullum or Category:Lecture notes. Note that there may eventually be other Name electricity basics pages that will show up in the same categories. What do you think? --Lonny 16:27, 11 October 2006 (PDT)

## Confusing

I find this page confusing. It should be a basic primer on electricity. The water analogy is in part helpful - but things go out the window when you start talking about series and parallel circuits in water before even saying what it is in electricity and why it's useful to know. Jarod997 (talk) 06:49, 6 May 2015 (PDT)

Hi Jarod,
Thank you for your input. Please feel free to start making changes, or to suggest specific changes here. I look forward to it!
Thanks again, --Lonny (talk) 09:04, 6 May 2015 (PDT)
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