For your amateur radio Foundation exam, you will be expected to know the formula associated with resistance – this is known as Ohm’s Law
The formula is V (Voltage) = I (Current) x R (Resistance)
This can be expressed in three different ways:
Voltage (V) = Current (I) x Resistance (R)
Current (I) = Voltage (V) / Resistance (R)
Resistance (R) = Voltage (V) / Current (I)
In the exam, you may be given a question where you are given two of the values, and be expected to calculate the third.
One of the best ways to help cope with calculating Ohm’s Law, is “the triangle”.
Cover up the letter for the value you want to calculate, to see what to do with the other two values to get the right answer.
As using the triangle generates lots of questions for students on our course, here’s a video showing just how to use it – with examples.
Please get a pen and piece of paper… and watch the following…
Hopefully, this short video guide helps to get you comfy with using the triangle for tackling Ohm’s Law exam questions.
