Ohm's Law

Ohm's Law states that the relationship between current, resistance, and voltage is as follows: The current in a circuit is directly propositional to the applied voltage and inversely proportional to the resistance.

voltage (V) = current (I) × resistance (R)

Understanding this relationship is important for fast, accurate electrical problem diagnosis and repair.

If you know two of the quantities, then you can calculate the third. A popular way to remember Ohm's Law is with a triangle.

Example: A 12-volt battery produces a current in the circuit of 0.5 A. What is the resistance?

R = V/I = 12 / 0.5 = 24 ohms.

The power wheel calculator

The power wheel calculator simplifies the calculation of all main electric parameters, i.e. voltage, current, power, and resistance; and clarifies the relation between these parameters.

Fill in the blanks

1) What is the algebraic formula for Ohm's law?

A) ______________

2) Find the Resistance for each combination of voltage 
   and current values using ohm's law?

i)   V = 5 Volt   I = 2 ampere     R = _________
ii)  V = 9 Volt   I = 1 ampere     R = _________
iii) V = 5 Volt   I = 0.02 ampere  R = _________

3) Find the voltage for each combination of resistance
   and current values using ohm's law?

i)    R = 200 ohm   I = 5 ampere   V = _________
ii)   R = 500 ohm   I = 2 ampere   V = _________
iii)  R = 1000 ohm  I = 1 ampere   V = _________

4) Find the current for each combination of voltage
   and resistance values using ohm's law?

i)    V = 5 Volt   R = 200 ohm   I = _________
ii)   V = 9 Volt   R = 250 ohm   I = _________
iii)  V = 5 Volt   R = 500 ohm   I = _________

Answers
1) V = I x R  2) i) 2.5    ii) 9    iii) 250
3) i)1000   ii)1000  iii)  1000
4) i) 0.025      ii) 0.036   iii) 0.01