The total voltage in the circuit stays the same. Only the voltage used by individual components changes. Here's an example using the formulas for series circuits:
Series Circuits Formulas:
Ohm's Law (stated 3 different ways):
E = I x R
I = E/R
R = E/I
E(total) = E(R1) + E(R2).... + E(Rn)
R(total) = R1 + R2.... + Rn
I(total) = I(R1) = I(R2).... = I(Rn)
Circuit 1
To learn everything about this circuit we can use a chart. Start by entering what we know:
Using the formula: R(total) = R1 + R2.... + Rn we can find the total resistance:
We can now use Ohm's Law in the form of I = E/R to find the total current in the circuit
From the formula: I(total) = I(R1) = I(R2).... = I(Rn) we can now determine the current in both resistors:
Lastly, we can use Ohm's Law E = I x R to find the voltage used by each of the resistors
Note: Power (P) is measured in Watts (W). The formula is: P = I x E
Circuit 2
In Circuit 2 resistor #1 is increased to 9 ohms with all other parameters remaining the same. Calculate the values for this circuit just as in Circuit 1.
Results are:
Note: The voltage used by resistor 1 increased and the voltage used by #2, the current and total power decreased.