A 6 V battery drives two lamps, L1 and L2, one on each parallel branch. The lamps split the current between them. Do they split the voltage too?
Look at where each branch starts and ends. Both ends of L1's branch connect straight to the battery's two terminals. L2's branch does the same: its two ends connect to the same two terminals.
The voltage between the battery's terminals is 6 V. So the voltage across L1 is 6 V. The voltage across L2 is 6 V too. Neither lamp gets a share. Each lamp gets the whole 6 V.
Two fans run in parallel from a 24 V supply. What is the voltage across each fan?
The rule does not care what sits on the branch. A lamp, a motor, or a large resistor on a parallel branch all have the full source voltage across them.
A 9.0 V supply drives a resistor and a buzzer on two parallel branches. What is the voltage across the buzzer?
Both ends of the buzzer's branch connect to the supply's two terminals.
Every branch of a parallel circuit has the full source voltage across it.
The voltage across the buzzer is 9.0 V.
A 15 V supply drives a lamp and a motor in parallel. The lamp's resistance is three times the motor's. What is the voltage across the lamp?
A 12 V battery drives a 20 Ω resistor and a 60 Ω resistor in parallel. What is the voltage across the 60 Ω resistor?
The 60 Ω resistor sits on its own parallel branch.
Every branch of a parallel circuit has the full source voltage across it. The branch's resistance does not change that.
The voltage across the 60 Ω resistor is 12 V.
Three heaters sit on parallel branches across a 120 V supply. What is the voltage across each heater?
How does this compare with a series circuit? First, recall the series rule:
In a series circuit, which quantity do the component voltages add up to?
Compare the two circuit types. In a series circuit, the component voltages add up to the source voltage. In a parallel circuit, every branch has the full source voltage across it.
A pump and a speaker are wired in parallel across a 12 V battery. What is the voltage across the speaker?
In a parallel circuit, lamp A's branch has more resistance than lamp B's. How do the voltages across the two lamps compare?
A voltmeter across one branch of a parallel pair of LEDs reads 4.5 V. What is the source voltage?