Current divider: everything you need to know about this circuit


In a previous article we already introduced the voltage divider and explained that there were more divider and multiplier circuits, such as frequency or current ones. Well, now let’s dedicate this entry to the current divider. As you can guess from its name, it is basically a circuit that can divide at its output the current or intensity of a circuit to lower values than those that enter it.

The truth is that all these circuits that can convert some values into others, either clock frequency, voltage or current as in this case, are very common and practical for the amount of uses that can be given to it. In addition, it is very simple to build and cheap, and can be a good experiment for electronics students who want to check with the polymeters the effect that has …

What is a current divider?
Current divider diagram and formulas

A current divider, as I mentioned, is a circuit that can divide a current intensity that exists at its input to other smaller intensities at its output. In order to realize this effect, only a few resistors are needed. Just as the voltage divider was composed of series resistors, or the voltage multiplier was diodes in parallel, the current divider is a series of stages composed of resistors in parallel.

Remember: series resistors = voltage divider, parallel resistors = current divider

So, if you have a current divider with two stages or two resistors in parallel, each one will be using a portion of the total current. That’s how you get to divide the current. In other words, if you use only two resistors, to calculate the output current, you can divide the resistance of R1 by the sum of R1+R2 and multiply it by the total current (input).

As you can see, you can calculate the current in each stage according to the value of the resistors. And if you want, you can add stages or resistances in parallel and modify the formulas to know the final current. Remember that the units must be in ohms, and the current in amps… Easy, right?

Principle on which it is based

And what is the principle of splitting the current? I don’t know if you have studied electronics or not, but when you study simple series and parallel resistance circuits, you are told in manuals and study books that when you put resistors in parallel the current is divided by several paths.

If you remember, because of the series resistors the voltage or voltage is distributed between them (voltage divider), but the current circulating through them is the same as that supplied. On the other hand, in the parallel resistors the voltage that passes through each one of them is the same, since their ends are connected directly to the main supply line. On the other hand, when talking about current for the parallel ones, the amperes are distributed among them because it does not circulate only through one path as in the series.

Principle on which it is based

You have already seen that to create a current divider you only have to have some resistances, make the necessary calculations as I have shown in the previous section and play with the stages and the values of the resistances to obtain the result you are looking for. The truth is that it is quite simple, I don’t have much more to say…

What you should consider is using, for example, a potentiometer as we did with the voltage divider. This way you can adjust the values and be able to experiment with a multimeter to see how it affects the variations of the resistance to the current. It is a quite educational practical exercise.

And a last note, if you remember when we saw the voltage divider I said that a common mistake was to think that if we coupled several elements parallel to its output we wouldn’t all have the same voltage. Remember that the resistance of each of the elements affects the voltage and the intensity, in fact, the current divider is based on these principles…

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