What Are Clamp Meters?
Clamp meters are a very convenient testing instrument that permits current measurements on a live conductor without circuit interruption. When making current measurements with the ordinary multimeter, we need to cut wiring and connect the instrument to the circuit under test as shown in Fig.1.
Using the clamp meter, however, we can measure current by simply clamping on a conductor as illustrated in Fig.2. One of the advantages of this method is that we can even measure a large current without shutting off the circuit being tested.
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| Fig.1 Measurement using multimeter | Fig.2 Measurement using clamp meter |
How to Measure DC Current
Clamp on to a conductor just the same way as with AC current measurement using an AC current clamp meter. In the case of DC clamp meters the reading is positive (+) when the current is flowing from the upside to the underside of the clamp meter.