Testström

Testström, in Swedish technical usage, refers to a controlled electric current used during testing and validation of electrical and electronic equipment. It is typically supplied by a current source and is distinguished from the nominal operating current of a device under test. The term appears in laboratory procedures, manufacturing QA, and development work as a way to simulate load conditions or to stress components under defined conditions.

Applications of testström include functional testing of power supplies, relays, fuses, and transformers, as well as dielectric and insulation testing. It is also used for characterizing response times, thermal behavior, and reliability under restricted current levels, or for pulsed and stepped load tests. In research and development, testström helps verify performance margins and fault conditions without applying full operating power.

Technically, a testström is produced by a current source or a programmable instrument capable of delivering constant or varying current. It can be DC or AC, and may take the form of pulsed, ramped, or stepped waveforms. Measurement during a test typically involves precision ammeters, shunts, or non-contact current probes, often with simultaneous voltage and temperature monitoring to assess electrical and thermal effects.

Safety and documentation are essential. Proper isolation, current-limiting, and protective equipment reduce risk during high-current tests. Test procedures are usually documented with defined parameters, tolerances, acceptance criteria, and traceability to standards and calibration records.