Kirchhoff's voltage and current laws are two laws that circuits abide by. They are two laws essential to electrical engineering, and are stated as follows:
- The algebraic sum of all voltages in a loop must equal zero.
- The algebraic sum of all currents entering and exiting a node must equal zero.
That's about as deep as we're going to go on these laws. I have mentioned these laws here because the voltage law is the one we will see in action in the next section, when we calculate why we've been using a 200 Ohm resistor in earlier chapters for our LED circuits.
With that, we have covered briefly three important electrical principles or laws – Ohm's Law, power, and Kirchhoff's circuit laws. It's now time to put these principles into practice. We will do this with an exercise to work out why we have been using a 200Ω series resistor in our LED circuits.
