contact modulation

contact modulation

[′kän‚takt ‚mäj·ə′lā·shən]
(electricity)
The use of a fast-acting relay, whose contacts make and break at a certain threshold current, to generate square waves from a sine-wave, rectified sine-wave or direct-current source.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.