Work out delta to star conversion instantly with clear inputs, formula shown and shareable results.
The delta-to-star transform replaces a triangle of resistors with an equivalent star: each star arm is the product of the two delta resistors touching that node divided by the sum of all three. It is the standard trick for reducing bridge networks that have no series or parallel pairs.
Delta to star
Ra = Rab x Rca / (Rab + Rbc + Rca), and similarly for Rb and Rc
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
When a network cannot be reduced by series and parallel combination alone — a Wheatstone bridge with a load across the middle is the classic case.
Star to delta: Rab = (Ra Rb + Rb Rc + Rc Ra) / Rc, and similarly for the other two.