Phyzzles: Series and Parallel Circuits!

In our electricity unit, we are learning about series and parallel circuits!

Series Circuit!

A series circuit has one path. The voltage is shared along the path and the higher resistance resistor will receive more voltage. All resistors in a series circuit on the same path with get the same current (one path, one current). The equivalent resistance of a series circuit is the amount of resistance that a single resistor needs to equal the overall affect of resistors in the circuit. For example, three 7Ω resistors would be equivalent to a 21Ω resistor. The equation to find the total equivalent resistance (Req) is

Req = R1 + R2 + R3...

To find the total current from the battery we use V = IR with the givens.

Ibatt = Vbatt / Rbatt

To find the voltage drop across three resistors, we use V = IR for all resistors and then add them together.

Let's find the Req! (pretend the kΩs are just Ω)
Req = R1 + R2 + R3
Req = 3Ω + 10Ω + 5Ω
Req = 18Ω

Let's find the Ibatt!
Ibatt = Vbatt / Rbatt
Ibatt = 9V / 18Ω
Ibatt = 0.5 A

Let's find the V drop!
V = IR
1. 1.5V
2. 5V
3. 2.5V
V = 9V

Parallel Circuit!
Parallel circuits have multiple paths or branches. The difference between the series and parallel is that if one resistor is cut off of a parallel circuit, the circuit can still work. If a battery was cut off of a series circuit, the current wouldn't be able to flow. Voltages in a parallel circuit are the total start voltage down the path.
The current total is equal to the sum of all currents

Itotal = I1 + I2 + I3

The Rtotal or Req of a parallel circuit is shown by this equation

1 / Req = 1 / R1 + 1 / R2 ...