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# What is delta/star and star/delta change?

Hello friends In this article we will know what is delta/star and star/delta change? And learn about many facts related to it.

## Delta/Star and Star/Delta Changes

There are some networks in which resistance are neither in series nor in parallel. A familiar case is a three-terminal network. Example :- Delta network or Star network.

In such situations, series and parallel Circuit It is not possible to simplify the network by rules. However, converting a delta network to a star and vice versa often simplifies the network and makes it possible to implement series-parallel circuit techniques.

## delta/star change

Three resistors R connected in delta across three terminals A, B and C as shown in Fig. 3.13 (i)AB RBC and RCA Consider it. These three delta-connected resistors are connected in the star with three resistors R.ARB and RC See Figure 3.13 (ii) so that the two networks are electrically equivalent.

If the resistance between any two terminals of one network is equal to the resistance between the corresponding terminals of the other network, then the two arrangements will be electrically equivalent It can be shown that RARB and RC The values ​​of K are given by:-

RA = RABRCA / (RAB + RBC + RCA,

Similarly, RB = RBCRAB / (RAB + RBC + RCA,

and RC = RCARBC / (RAB + RBC + RCA,

### How to remember?

A fascinating way to remember it. Referring to Fig. 3.14, the star-connected resistance RARBand RC Electrically Delta Connected Resistors RABRBC and RCA We have seen above that:

RA = RABRCA / (RAB + RBC + RCA,

For example, any arm of star connection :-

= product of two adjacent sides of the delta / sum of the sides of the delta

## Star/Delta change-

This means replacing the star-connected network in Fig. 3.13 (ii) and the equivalent delta-connected network shown in Fig. 3.13 (i) to show that RBCRCA and RAB The values ​​of K are given by :-

RBC = RB + RC + RBRC / RA

RCA = RC + RA + RCRA / RB

RAB = RA + RB + RARB / RC

### How to remember?

There’s an easy way to remember it. Quoting Fig. 3.15, the star-connected resistance RARB and RC The electrically delta connected resistors are equal to RABRBC and RCA We have seen above:-

RAB = RA + RB + RARB / RC

Resistance between two terminals of Delta = sum of the star resistances connected to those terminals plus the product of the same two resistors divided by the third star resistance.

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