DMM continuity test

Thread Starter

Marc0

Joined Nov 28, 2011
42
I was wondering about what's the max resistance value allowed between two points in a circuit, to say that there's continuity between them.
This question arose while I was working with some SMD resistors (a few ohms) and noticed that my DMM was buzzing in continuity mode when testing some of those
 

vk6zgo

Joined Jul 21, 2012
677
I was wondering about what's the max resistance value allowed between two points in a circuit, to say that there's continuity between them.
This question arose while I was working with some SMD resistors (a few ohms) and noticed that my DMM was buzzing in continuity mode when testing some of those
Easy answer--- don't use your continuity mode to measure resistors.

Seriously though,it is a problem if you are checking cables which may have high resistance connections.
The readout will usually show a difference,even though the "beep" is the same.
Of course,if you have to look at the display,why not just use the Ohms range?
 

Thread Starter

Marc0

Joined Nov 28, 2011
42
Ok...but my question was more conceptual than practical.
What resistance value is considered acceptable to say that 2 points are in continuity? Is there a standard?
 

Lundwall_Paul

Joined Oct 18, 2011
236
Take your DMM to a decade box to hear when the tone comes on. I believe that I did this with a Fluke and if I remember correctly I heard the tone around 50 ohms.
 

Thread Starter

Marc0

Joined Nov 28, 2011
42
Did something similar with a variable resistor...my DMM starts buzzing at about 30 ohms.
Yesterday was testing a circuit, there was a smd resistor (5 Ohms) placed in series between the PSU and some opamps. The opamps weren't getting power so I started checking the circuit for continuity...checking that resistor there was no continuity, but didn't know if it was because of the too high resistance or because the resistor was blown.
End of the story: the resistor was blown...for my DMM under 30 Ohm there is continuity, if the resistor is 5 Ohms and there's no continuity...well it's the resistor fault.
 
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