Voltage vs. Current
2. The Key Differentiators
Voltage and current are often used together, but they represent different things. Voltage, sometimes called potential difference, is the "push" that drives the current through the circuit. It's the electrical pressure that forces electrons to move. Think of it like the water pressure in a pipe. Higher pressure means more force pushing the water through.
Current, on the other hand, is the flow of electrical charge. It's the amount of electrons actually moving through the circuit. Think of it like the amount of water actually flowing through the pipe. Higher current means more water is moving.
In a parallel circuit, the voltage stays consistent across all branches. However, the current divides. Each branch "consumes" the current it needs based on its resistance, and those individual currents add up to the total current drawn from the source. Imagine several lights connected in parallel: each receives the full voltage (ensuring equal brightness), but the current flowing to each will depend on the bulb's wattage. All of those individual currents add up to how much current the power supply needs to provide.
Understanding this distinction is key. To reiterate, the keyword term here is that parallel circuits primarily affect current. "Current" functions as a noun, defining the quantity being altered within the electrical circuit. If you want higher voltage, you'd typically look at series circuits, not parallel ones.
The Math Behind Parallel Circuits (Don't Worry, It's Not Too Scary!)
3. Calculating Equivalent Resistance and Total Current
While we don't need to become electrical engineers overnight, knowing a little bit of the math can be helpful. The key equation for parallel resistors (components that resist the flow of current) is: 1/Rtotal = 1/R1 + 1/R2 + 1/R3 + ... and so on. Where Rtotal is the total equivalent resistance of the parallel circuit, and R1, R2, R3, etc., are the individual resistances of each component.
See? It's not that bad. It simply states that to find the total resistance of parallel resistors, you have to add the inverse of each individual resistor and then take the inverse of that sum. For example, let's say we have two resistors: one at 10 ohms and another at 20 ohms. 1/10 + 1/20 = 3/20. Then, take the inverse of 3/20, which is 20/3 or approximately 6.67 ohms. The total resistance of our two parallel resistors is 6.67 ohms.
Once you know the total resistance, you can use Ohm's Law to calculate the total current: I = V/R. Where I is the current, V is the voltage, and R is the resistance. Let's say our voltage source is 12 volts. The total current would be 12 volts / 6.67 ohms = approximately 1.8 amps. This 1.8 amps is the total current drawn from the voltage source in order to power the parallel circuit.
The current then splits based on the individual resistances of each branch. Using Ohm's law again, the current through the 10-ohm resistor would be 12 volts / 10 ohms = 1.2 amps, and the current through the 20-ohm resistor would be 12 volts / 20 ohms = 0.6 amps. Notice that 1.2 amps + 0.6 amps = 1.8 amps, the total current drawn from the voltage source. Math is cool, isn't it?
