Examples on Series and Parallel Circuits

Example 1

We have a series circuit like this. What is the total voltage, resistance and current?
First, we have to find out the total voltage , and then resistance , and finally you can find out the current.
Total voltage is 9 + 1 + 16 + 4 = 30 V
Total resistance is 30 + 10 + 40 + 20 = 100 ohm
Using ohm's law, I = V / R, then we can find out the total current.
I = 30 / 100 = 0.3 A


Example 2

If you have a parallel circuit like this, what is the total resistance and voltage? And voltage and current on A, B, and C?
In order to find out the total voltage, we have to find out the total resistance. Using equation 5, we can find out the total resistance.
1/R = 1/15 + 1/15 + 1/30 = 5/30, R = 6 ohm
Then using ohm's law,V = I R, we can find out the total voltage.
V = 5 * 6 = 30 V
Using equation 4, we now know the voltage on A, B, and C, which is 30 V each.
Using ohm's law again, we can find out the current on A, B, and C.
IA = 30/15 = 2 A,
IB = 30/15 = 2 A,
IC = 30/30 = 1 A .
When you add up all the current (using equation 6), we get 5 A which is the total current.