Choosing the best multimeter
A typical diagnostic tool for technicians in the electrical or electronics industry, multimeters, as the name suggests, can measure current, voltage, resistance, and continuity. These are the basic measurements that a simple multimeter can provide. As a technician becomes more experienced, complex multimeters that give more measurements are required. There are analog multimeters that have a moving pointer to indicate values and a digital one with digital readouts. Today, digital multimeters or DMMs are used more than analog ones.
Use of multimeters:
Multimeters are used to test circuits during debugging and batteries. Generally, the range must be established before obtaining the actual measurements. Depending on the expected value, this range can be set manually or has auto-ranging capabilities. A range of twenty microamps to milliamps at 10 amps max, 200 microvolts to 600 volts, and 200 ohms to kilo ohms to 20 mega ohms…these are the typical ranges. It can be used for AC and DC current by turning the knob appropriately. Auto-ranging multimeters display the unit for the reading.
A multimeter shows the average current. Capacitors and inductors have an initial surge in current that cannot be detected by a multimeter and would require an oscilloscope to detect and measure.
Continuity tests on diodes are to detect their polarity. Diodes (and resistors) must be separated from any power source before making measurements on them. In a circuit, the continuity of the diodes is indicated by a beeping sound.
multimeter applications
HVAC systems
amateur radio applications
mobile repair
Multimeter Categories
There are four categories based on their applications ranging from low risk: CAT I to high risk CAT IV.
Each category rating specifies the safe step voltages for the meter’s measurement ranges. Category-rated meters have built-in overload current protection.
Some advanced features of multimeters:
Capacitance reading
frequency reading
With a thermocouple probe, temperature readings are possible
Reading storage and transfer capabilities via USB
· Every technician has a multimeter at hand, as it is the first diagnostic tool available for debugging circuit designs in electronics.
Ability to interact with computers.
What to look for when buying a multimeter:
These are the conditions that must be met when choosing a multimeter:
· Safety Features: Must be CAT rated and have a built in fuse for high currents.
· Voltage range and accuracy of readings: Depends on what you buy it for. If it’s for household circuits, the measurements don’t need to be as precise as you would for electronic circuits. You would need both AC and DC metering capabilities in most cases.
· Durability and size: it must be of good quality to withstand a few drops from time to time. Many technicians prefer a convenient size that fits in your pocket, but for an irregular user, a large size might be more useful, with easy-to-read values.
· Accessories: probes with banana plugs, needle-tip probes, alligator clips, clip probes, and a temperature probe that is useful in HVAC applications.
· Warranty: Some manufacturers offer a lifetime warranty, the term lifetime is defined differently for each one! Others give a one year warranty. A lifetime warranty is always better, whatever term you state, it would be better than a one year warranty.
Price: Don’t compromise on price if that’s a complicating factor, as all other features between models are the same. This is a security issue, so if all the security features are in place, feel free to spend a bit more.
