Single-phase bridge-type cycloconverter In power electronics, a single-phase bridge cycloconverter (line-commutated, using two anti-parallel bridges) employs how many thyristors in total?

Introduction / Context:
A single-phase bridge-type cycloconverter directly converts AC at one frequency to AC at a lower frequency without an intermediate DC link. It accomplishes this with two full thyristor bridges connected in anti-parallel to synthesize positive and negative portions of the low-frequency output from the mains supply.

Given Data / Assumptions:

• Configuration: two full-bridge converters connected anti-parallel (one for positive current, one for negative current).
• Each full bridge uses 4 thyristors (line-commutated SCRs).
• Gate control determines which bridge conducts at a given instant to shape the output waveform.

Concept / Approach:
Counting devices is straightforward: a standard single-phase full bridge requires four SCRs arranged as two legs. Two such bridges are required in anti-parallel so that current can be driven in either direction at the output while remaining line-commutated. Therefore, total SCRs = 4 + 4 = 8.

Step-by-Step Solution:
Identify one full bridge → 4 SCRs.Duplicate for the opposite polarity bridge → another 4 SCRs.Total thyristors used = 4 + 4 = 8.

Verification / Alternative check:
Most text-book schematics of single-phase bridge cycloconverters clearly show two bridge groups, each with four controlled devices, confirming the count of eight.

Why Other Options Are Wrong:
Any claim of fewer than eight devices would imply a half-controlled bridge or non-bridge topology; more than eight would correspond to multi-pulse or multi-module designs, not the standard single-phase bridge cycloconverter.

Common Pitfalls:
Confusing the cycloconverter with a single-bridge AC regulator (which uses antiparallel SCRs or a TRIAC) or with a DC–AC inverter. Cycloconverters specifically need two full bridges for bidirectional current control.

Final Answer:
True