Voltage and Current
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[edit] Voltage and Current
[edit] Now The Details
The picture shows a series circuit and a parallel circuit. This is how voltage and current are related in such circuits:
- Series Circuit
The electrical current flows from the power supply into bulb A, out of bulb A and into bulb B, out of bulb B and returns to the power supply.
The current flows single file through both light bulbs, and the light bulbs have the same resistance (we are assuming the bulbs are identical). Ohm's law tells us that I = V / R, or V = I ยท R, and since the current I and the resistance R are the same for both bulbs, the voltage V on each bulb is also the same.
Since the supply voltage is 12 V, that means there is a voltage of 6 V on each bulb.
- Parallel Circuit
The electrical current flows from the power supply to the junction that leads to 2 identical light bulbs. The bulbs are identical, and they are both connected to the 12 V of the power supply. The missing piece of the puzzle is the current flowing through each bulb. Ohm's law tells us that I = V / R. Since the voltage V and the resistance R are the same for each bulb, the current I flowing through each bulb is also the same.
The picture labels the current flowing into the parallel circuit with Y, so the current flowing through each bulb is Y/2.
[edit] General Rules
- Voltage
In a circuit with two devices in series, the total voltage on the circuit is divided up between the devices. If the devices have the same resistance, there is half of the total voltage on each device.
- Current
In a circuit with two devices in parallel, the total current flowing through the circuit is divided up between the devices. If the devices have the same resistance, there is half of the total current flowing through each device.
[edit] See Also
- Voltage (Wikipedia)
- Current (Wikipedia)
- Direct current (Wikipedia)
- Alternating current (Wikipedia)
- Ohm's law (Wikipedia)
