You are correct that C and D batteries are both 1.5 volts. In fact, AA and AAA batteries are both 1.5 volts. It is only when you compare them to each other that they become different values.
The voltage of any battery is the measure of energy that can be released by the battery when it is connected to a load. Batteries have different voltages depending on how many cells they contain. For example, two AA batteries will always be 1.5 volts because they contain one cell each. A single D cell battery will also be 1.5 volts if it is not connected to anything else. But if we connect a lamp bulb or radio circuit to a D cell battery, it will light up or run through its cycle as electricity flows into it from the battery through the wire connections.
Electricity is the flow of electrons through a conductor such as a copper wire. When there is no resistance across which to flow, such as with a direct connection, then there is no current flowing and the voltage remains the same. As soon as there is some resistance present, however, then there will be a small amount of current flowing which causes the voltage across the resistor to drop slightly. The voltage drops even more when more resistance is added.
Why not just use all AAA batteries if they're the same voltage and make everything lighter and smaller? However, there is a significant difference between them all. The capacity of a battery is how much power it can deliver over time. The more mAh (milliampere hours) the battery can supply, the longer it can be expected to last without recharging. C batteries have a capacity of 1.5 milliamp hours (mah), while D batteries have twice that amount: 3 mah.
This means that you can expect C batteries to last for one hour per milliampere hour, or 1/3 of their total capacity. D batteries will last two hours per megohm hour, or 2/3 of their total capacity. There are other factors that determine how long a battery will last, such as how often it gets charged and drained, but this gives an idea of how much power each type of battery can supply.
It is also important to note that battery capacity does not always correspond with size. Small batteries can have more than one hundred times the capacity of large batteries! It's therefore important to choose batteries that match up with your project needs. For example, if you need something that lasts for a long time, you should select larger batteries than if you need something that runs for short periods of time.
AAA, AA, C, and D batteries are all rated at 1.5 volts, but there is a significant variation between them all, aside from physical size. The D-size battery has a higher current rating than the C, AA, and AAA-sized batteries. This means that you can use less expensive D-size batteries in devices that require more power than C sizes.
As well as being smaller, the D-size battery is also capable of delivering more power for longer periods of time. This is because it uses materials that are able to hold more charge per unit volume, so they can be packed more densely into a given space.
The D-size battery is commonly used in remote controls, flashlights, and other portable electronics products. It's also a popular choice for powering tools due to its ability to deliver high currents with low voltage drops.
Cells come in different capacities, from 100 milliamps (mA) hours ($10-$15 per thousand mAh) up to 20 amperes (A) hours ($500+ per thousand mAh). At first glance this may not seem like a lot of difference, but when you start multiplying capacity by average usage times you get an idea of how large these differences can become. For example, if you needed a battery that could power a light bulb for 10 hours then you would need a cell with 200 mA hours ratings.
Most AAA, AA, C, and D batteries have a voltage of about 1.5 volts. Assume the batteries in the diagram have a rating of 1.5 volts and 500 milliamp-hours. The four batteries connected in parallel will create 1.5 volts at 2,000 milliamp-hours. This is equal to 20 amps for two seconds.
The current flow through a circuit is measured in amperes (amps). The more current that flows through a circuit, the faster the wires will heat up and the shorter their life span will be. Batteries have an average life span of three to five years. If you use more than 500 milliamp-hours of power, then you should change the batteries every year.
Parallel circuits can be used to make devices that use more electricity work longer. For example, six 1.5 volt batteries in parallel would provide 12 volts and 90 amps for five minutes. This would damage most appliances that use standard AC current such as lamps, radio receivers, and electric motors.
In conclusion, one-half volt is not enough to light an LED bulb, but 12 volts is enough to run an LED lamp or flash light. Batteries can deliver much more power than what's needed so use caution not to exceed recommended limits.
Four batteries connected in series will provide 6 volts at 500 milliamp-hours.
The voltage of four D cells is about 3.3 volts. The voltage of four D cells can be divided among two circuits by connecting them in parallel. Each circuit will then have 1.5 volts available. Or, the voltage of four D cells can be combined with that of another set of four D cells to make eight D cells with a total voltage of 12 volts. This last method uses all the D cells in a battery pack. It is not recommended because it uses more power than necessary.
Four D cells connected in parallel can supply as much current as twelve D cells connected in series. However, the voltage of four D cells is slightly less than that of twelve D cells. So there is some loss due to resistance which decreases the amount of current that can flow through the load.
D cells are used most often in flashlight applications because they are easy to find and inexpensive. They usually have a life expectancy of one day when used regularly. However, D cells do require special care when being stored for long periods of time or used intermittently.
The voltage of D cells varies depending on how they are used.