Amateur Radio – remembering Ohm’s Law with the VIR triangle (and the PIV triangle)

For the Amateur Radio license exams (for most countries) you need to remember Ohm’s Law, which is easily remembered by the Ohm’s Law triangle:

 V
I R

where:

V = voltage (volts)

I = current (amps)

R = resistance (ohms)

To calculate any value knowing the other 2, cover the value you need with your finger and then use the remaining calculation, e.g.

V = I x R

I = V / R

Similarly for Power, use the PIV triangle:

 P
I V

where:

P = power (watts)

I = current (amps)

V = voltage (volts)