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[tech notes]
5

Ohm's law 
[meter]

Ohm's law states that current is directly proportional to voltage and inversely proportional to resistance, so the higher the voltage the higher the current - as long as the resistance remains constant.  Except as we always see, the current is also determined by the resistance (resistance is the opposition to current flow).  as long as voltage is constant, the higher the resistance - the lower the current and visa-versa.

Current = I
Voltage = E
Resistance = R

 

Ohm's law can be shown by three different formulas 

To find Current   I = E/R
To find Voltage   E = I x R
To find Resistance  R = E/I

[pie]

 

Ohm's Law Circle
Use the circle by covering the unknown value with a finger.
(Example if the unknown value is Voltage - cover the "E" the equation remaining is I x R).

 


[meter]

Power

Besides the three basic electrical units (current, voltage and resistance), there is a forth unit - Power.  The measurement of power is "Watts".
Power is the quantity of work done in a determined amount of time.
One Watt is equal to the work done by one volt moving a current of one ampere.

Power Formulas
Power is directly proportional to both current and voltage.
So the equation is :
P = I x E

 

The Circle shows three formulas for each quantity using the power formula and Ohm's Law.

Using the circle you can find a correct formula for any problem if two quantities are known.

 

 

 

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