How can I calculate voltage drop in a parallel circuit?

In a parallel circuit, the voltage drop across each component is the same. This is one of the key characteristics of parallel circuits.
Explanation:
1. Voltage in Parallel Circuits: In a parallel circuit, all the components are connected across the same two points, so the potential difference (voltage) across each component is the same.
o If you have a power source (like a battery) with voltage VtotalV_{\text{total}}, then the voltage across each branch of the parallel circuit will also be VtotalV_{\text{total}}.
2. Current in Parallel Circuits:
o The total current in a parallel circuit is the sum of the currents through each individual resistor (or component).
o Ohm's law (I=VRI = \frac{V}{R}) applies to each branch, so the current through each component depends on the voltage across it and its resistance.
Key Formula:
The voltage drop across each resistor in a parallel circuit is the same as the total applied voltage, i.e.,
Vdrop=VtotalV_{\text{drop}} = V_{\text{total}}
Example:
• Suppose you have a parallel circuit with a 12V battery and two resistors, R1=4 ΩR_1 = 4 \, \Omega and R2=6 ΩR_2 = 6 \, \Omega.
• The voltage drop across both R1R_1 and R2R_2 will be 12V each, because they are in parallel.
To Summarize:
In a parallel circuit, the voltage drop across each component is equal to the source voltage. You do not need to calculate the voltage drop for each resistor separately—just use the total voltage from the power source for each component.