A parallel circuit is one in which current can flow through several paths simultaneously.
circuit with 4 resistors
Notice that unlike a series circuit in this circuit current flows through resistors 1, 2, 3 and 4 simultaneously. If you stopped the flow of current at any of those resistors, current would still flow through the others. See circuit this concept.
interruption of flow through a branch in a parallel circuit. Does NOT affect the other branches
Parallel Circuit Rules and Formulas
Total Voltage is the same or the voltage on any resistor. The voltage on all resistors is the same.
Total Voltage = Voltage at resistor 1 = ...Voltage at Resistor n
Vt = V1 + V2 + ... Vn
Total Current is the sum of the individual currents on the different resistors.
Total Current = Current at resistor 1 + Current at resistor 2 + ... Current at Resistor n
To add fractions, I must find a common denominator. In this case, it is 9. We know that because 60 is divisible by 4, 12, 30, and 4.
1/Rt = 1/30 + 1/30 + 2/30 + 1/30
Notice the third fraction becomes 2/30 instead by 1/30 in order for all fractions to have a common denominator.
1/Rt = 5/30
Now, divide both the numerator and the denominator by a number that will turn the numerator into a 1. Let's divide both numbers by 3.
1/Rt = 5 ÷ 5 / 30 ÷ 5 = 1/6 1/Rt = 1/6 Rt = 6
Another way of nothing this problem is by using the circuit totals and using ohm's law
First, we calculate the circuit's total current
It = 2A + 2A + 4A + 2A It = 10A
Then, we calculate the circuit's total voltage. If we calculate the voltage at any resistance, that will be the total voltage. Let's do it on the first resistance.