The composite resistor: serial, parallel and mixed compound

Assemble any scheme we necessarily use resistors, as usual in all the well-known law, it turns out that the desired nominal resistance is not at hand. And out of this situation can be assembled composite resistor. That's about it and will be discussed in this article.

To assemble the composite resistor need to connect several resistors either parallel or sequential manner, and so you can get the required resistance.

In fact, these actions are in practice very often used. Fans of homemade and repairers with the experience I will not lie. So let's quickly go over the basic rules of serial and parallel connections.

Serial connection of resistors

In the diagram, such a compound is as follows:

As can be seen from the scheme we are made replacing a single resistor on several assembled in the chain. The resistance of both variants the same.

To calculate the total resistance sufficient to recall a formula that is:

In this case, remember the following rule: The main role is played in such a chain resistors with the highest resistance. That is, if you are a chain of resistance: 1000 ohm, 50 ohm and 10 ohm resistor and remove the 10 ohms, the total resistance has not changed much, but if you remove the resistor 1 kW, the total resistance to change dramatically.

parallel connection

In Scheme parallel connection basically depicted as follows:

In this case, for calculating the total equivalent resistance necessary to use a different formula, which is as follows:

If delivered in parallel only two resistors, then the formula is simplified

Also if thus connect resistors with the same nominal value, the formula for calculating the total resistance is substantially simplified.

mixed compound

Sometimes it is necessary to receive the non-standard resistance in which case the mixed compound is used.

To calculate the overall resistance of such a circuit it is split into serial and parallel sections, and produce the calculation.

Little experience

To clearly see in action parallel and serial connections of resistors let We conduct a simple experiment and take a pair of resistors 100 ohm and 330 ohm nominal value and connect them consistently.

As you can see, the meter shows the amount of resistance.

Now combine the same resistors in parallel.

We received a total resistance of 77.8 ohms, which is less than the resistance of the resistor to 100 ohms.

An important addition in the implementation of the composite resistor

If you need to implement an integral resistor, apart from the resistance you also very important to consider another option - the nominal power dissipation.

Consider a simple example. Let's say you need to replace bad resistor to 100 ohms designed for power dissipation 1W. To do this, you can take the 4 resistors of 25 Ohm and connect them in a consistent manner.

Since a series connection of current through the circuit all flows elements identical, then the power dissipation of each resistor of 25 Ohm shall be at least 0.25 watts. In this case we just obtain the composite resistor with a total resistance of 100 ohms and 1 watt.

conclusion

That's all I wanted to tell you about the composite resistor of the parallel, serial and mixed compound. If the article was useful to you, or are interested in, then put the Like. Thank you for your attention!