Consider the DMM is now in Ammeter mode as essentially a wire through which the current flows to the main circuit. In this configuration, the DMM becomes a part of the circuit and disconnecting any probe will break the circuit and it won’t work. The measured current is displayed on the DMM display. Finally n Can I destroy a Multimeter? Yes of course you can if it’s not connected properly and set to the wrong function. The cheaper ones won’t pass the drop test either! n How much are they? They range from £10 to £300 and more. It really depends on the make, type and quality. A cheap one will do most of the basic functions and perform reasonably well, whereas a Fluke looked after properly will last years. Mine is over 20 years old, used daily and still working well. n What types of DMM are there? A basic DMM will measure Continuity, Resistance, Voltage, Current (d.c. only) and Diodes, other types will measure capacitance, frequency, temperature and transistors. They can be auto ranging, auto switch off and measure a.c. Current too. There are other types of Multimeters, such as analogue, digital, bench and clamp meters. The CAI Training Programme This CAI 2-day course is designed to give delegates a greater understanding of the fundamentals taught. Be able to apply them in their working environment and give a broad- based underpinning knowledge in preparation for other industry training. The Essential Principles for Installers course is one of the training courses run by the CAI. See the complete programme of courses in the handout available at EC 2024.
DC Current To measure d.c. Current, set the knob of the Multimeter to DC Current measurement. This DMM shown here can measure DC Current from few µA to 5A. The range is sufficient for measuring current in LEDs. Set the range to 200mA and connect the Multimeter as per the following circuit.
Fluke DMM measuring the d.c. Current through the circuit, it’s 62.8mA
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CAI Feedback Spring 2024
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