Question

Why is a choke placed between the power supply and the bus line?

KNX BasicLearnSystem OverviewMedium
Answer

B — To stop the power supply's voltage regulator from correcting (cancelling) the AC information voltage

Correct: Without the choke the regulator would try to correct the AC information voltage, causing a tug of war with the sending device.

Source

KNX Basic Course Documentation — 11 — p. 52

All proposed choices (exam context)
  1. A.To increase the bus voltage from 24 V to 30 V
  2. B.To stop the power supply's voltage regulator from correcting (cancelling) the AC information voltage
  3. C.To convert the 30 V DC into AC for the devices
  4. D.To protect the devices against short circuits
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Last updated: 19 May 2026

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