voltage drop across resistors

[estradiol9]

Why is there no voltage drop across resistors in parallel but there is a voltage drop for resistors in series?

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[milski]

There is always voltage drop. In the case of parallel resistors, it's independent of the other resistor and is the same as it would be if the other resistor did not exist.

 

[LoLCareerGoals]

Same current flows through 2 resistors in series. (Think of it as a water stream and follow it through the circuit).
Since (voltage across a resistor) = (current that flows through a resistor, I)X(resistance of the resistor, R), for a series connection I is the same and R may or may not be the same, hence voltage drop is proportional to resistance (bigger one will have a bigger voltage across it).

In a parrallel connection, "the water stream" splits into 2 or more possible paths. Different current flows through different paths. Voltage across each resistor is the same (because voltage is defined as potential #1 - potential #2) and since multiple resistors are connected to the same 2 points the difference in those 2 potentials and thus voltage is the same. current is not however, more current will flow through the "less resistant" branch. Think of a inf Ohm resistor as an open circuit and 0 Ohm resistors as a short cirtuit/wire.