Multimeter range questions - Page 1
Forum section: electronics / beginners

author: mhost
author_rank: Newbie
timestamp: January 06, 2024, 12:33:22 am
content: I am shopping for a new better multimeter. I am planning to get a clamp meter. But I have a few questions.One thing that I've recently need to test is something with very low millivolts. When looking at the specs of the different options I'm considering, they don't list how low they go.For example, the Klein cl390's lowest range is 400mV whereas the cl320's lowest range is 200mV. Would one of these potentially be more accurate at reading 600mv and would one of these be able to go lower than the other?I'm leaning towards the Klein cl390 mostly because it adds DC current testing. Not really sure I'll ever need that, but just in case. I do car work, and could potentially see wanting to test the current in there. What other typical use cases are there for DC current testing?Last question, from looking at the manual, I get the impression that current testing on the Klein clamp meters can only be done through the clamp. Anyone know if it could be done through the leads as well? I'm aware of the safety concern, just want to check.Thanks

author: Jwillis
author_rank: Super Contributor
timestamp: January 06, 2024, 01:08:01 am
content: Clamp meters are better suited for high current and high voltages. They don't measure current with any real accuracy lower than 5A in most cases. You will get much better accuracy with a standard multi-meter for low voltage and low current under 10A applications. The higher the voltage and current your measuring the less accurate you need to be. The lower the voltage and current the more accurate you need to be. It depends on what voltages and currents you intend on measuring the most.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 06, 2024, 03:41:28 am
content: The two meters have the same accuracy and resolution. Both can display down to 0.1mV but that 0.1mV is meaningless. Both measure current with the clamp only except for the 200uA range which measures using the test proble. This is primarily for measuring flame rod current in furnace.But this is more resolution than you can get with the expensive Fluke 378.

author: Jwillis
author_rank: Super Contributor
timestamp: January 07, 2024, 02:53:23 am
content: The cl320 has no DC current other than the 200uA range with the probes. Anything above 200uA DC can't be measured.The cl390 has DC current measurement with the clamp. But it has a minimum of 300mA. The probes have a maximum of 200uA, This leaves a gap between 200uA and 300mA that can't be measured.

author: nightfire
author_rank: Frequent Contributor
timestamp: January 07, 2024, 04:35:44 am
content: Question here: Is the clamp meter decision due to the benefit of simply having one "all-in-one" device available, or due to budget considerations?In which Applications you would need to measure small voltages or currents?Reason: Small Volts can be easily measured, if the multimeter has a high internal resistance, small currents are a bit more problematic, specially when measuring with a clamp. (Most Clamp meters only do AC)Regarding precision, the clamp meters usually have some multimeter part that uses a lesser accuracy and resolution than a "real" multimeter- question here: How much precision do you need?Greenlee seems to rebadge Brymen Clamps in Canada, the CM-450 uses 1 Gigaohm resistor in the mV range, to get better and more precise readings.