Assembly to test the degree of corrosion present in e.g. sub-soil steel pipes incorporates blocking choke

摘要

Assembly tests the degree of protection from corrosion enjoyed by a metal object (1) with cathode anti-corrosion protection. The assembly incorporates a voltmeter (8) that is brought into contact with the test item via an RC blocking choke (6, 7) to suppress alternating current at two or more fixed frequencies.