Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Wiring Fundamentals: Ohm's Law

Watch This Course

$99 USD $49.50 USD

Or 8 easy payments of only $6.19 Instant access. Easy checkout. No fees. Learn more
Course Access for Life
60 day money back guarantee

Ohm's Law


00:00 - As we have now discussed three of the fundamental electrical concepts, and used an analogy to the physical world to understand better how they relate to one another, it's time for some of that math I warned you about earlier to formalise that relationship, and show how it can be used to ensure our wiring harness design is correct.
00:17 There is a simple formula that relates voltage, current, and resistance, known as ohm's law.
00:23 This formula states that between any two points in an electrical circuit, the voltage difference is equal to the current flowing, multiplied by the resistance that current encounters.
00:33 This is commonly stated as V=IR The beauty of this equation is that it can be easily rearranged to calculate any of the three fundamental values in an electronic circuit.
00:44 As long as we know the other two.
00:47 Current for example is equal to the voltage divided by the resistance, I=V/R And resistance is equal to the voltage divided by the current, R=V/I In the automotive electrical world, a most common use of ohm's law, is to calculate the current that will flow in the circuit when we apply a certain voltage to it.
01:08 For example if we know a particular fuel injector has a resistance of 6.9 ohms and we're going to apply an electrical pressure of 13.8 volts across it, we can calculate the resulting current that will flow by dividing the voltage by the resistance.
01:22 13.8 volts divided by 6.9 ohms, gives us a current of two amps.
01:27 This allows us to determine the smallest size of wire we can safely use to run this injector.
01:33 This saves us money as smaller gauge wires are cheaper, plus also helping us to reduce both the bulk and weight of the wiring harness.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?