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Electrical Formulas & Equations:


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Resistance (Ohms Law)

V=IR

Ohms Law Formula. V=IR

Where:- V=Voltage (v), I=Current (A), R=Resistance ().


Mass

F=ma

Mass Formula. F=ma

Where:- F=Force (N), m=mass (kg), a=acceleration (ms·²).


Force

F=mg

Force Formula. F=mg

Where:- F=Force (N), m=mass (kg), g=acceleration due to gravity (ms·²).


Torque

T=fd

Torque Formula. V=IR

Where:- T=Torque (Nm), f=force (N), d=distance (m).


Work Done

W=fd

Work done Formula. W=fd

Where:- W=work done (or energy) (j), f=force (N), d=distance (m).


Power

P=wt

Power Formula. P=wt

Where:- P=Power (w), w=work done (or energy) (j), t=time (s).


Coulomb

Q=It

Ohms Law Formula. Q-It

Where:- Q=quantity of electricity (c), I=Current (A), t=time (s).




Resistivity

þ=LA

Resistivity Formula. þ=LA

Where:- þ=Resistivity (m), L=Length (m), A=Area (ms·²).




Magnetic Flux Density

B=ΦA

Magnetic Flux Density Formula. B=ΦA

Where:- B=Magnetic Flux Density (T), Φ=Magnetic Flux (mWb), A=Area (ms·²).


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Induced emf

E=BLV

Induced emf Formula. E=BLV

Where:- E=Induced emf (V), B=Magnetic Flux Density (T), L=Length (m), V=Voltage (ms·¹).




Transformer Ratios


Tranformer Ratio.

Where: Up=Primary Voltage (V), Ns=Secondary Turns, Us=Secondary Voltage (V), Ns=Primary Turns. These two (2) Principles can be combined and described using the following formula:

Further Tranformer Ratio.

Below, Is a better way to look at it...

Further Explaination Of Tranformer Ratio.

Where:- Is=Current Amperes Secondary, Ip=Current Amperes Primary.


Efficiency


Efficiency Formula.

Below, Is a another way to look at it...

Efficiency Formula (V2).

* Task: If you don't already know them, look up the symbols used in working out efficiency.



Supply Voltage Formula (Vs)

√R²+XL²=Vs

Supply Voltage Formula. √R²+XL²=Vs

Supply Voltage Formula. √R²+XL²=Vs

Where:- R²=Resistance Squared, XL²=Inductive Squared, Vs=Supply Voltage.



Resistance

R=þl/a

Where:- E=Induced emf (V), B=Magnetic Flux Density (T), L=Length (m), V=Voltage (ms·¹).


R=þl/a

þ (rho) is the symbol used for Resistivity.

Remember:
Increasing the length, Increases the Resistance.

Increasing the Area (csa) Decreases the Resistance.


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