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Products => Test Equipment => Topic started by: pherdie on July 07, 2016, 08:10:47 pm

Title: Five volts on DMM diode checks, is it an issue for concern?
Post by: pherdie on July 07, 2016, 08:10:47 pm
Deciding whether to purchase a Keysight 34461A or a Fluke 8845. Both employ five volt sourcing on diode checks.

There has been some concerns expressed about the use of five volts and potential damage to certain components, yet, at least two major high end manufacturers have moved to the higher five volt parameter.

Something I should consider in my purchase?
Title: Re: Five volts on DMM diode checks, is it an issue for concern?
Post by: D3f1ant on July 07, 2016, 08:36:49 pm
5V is great, lets you test modern LEDs. Guess if you're regularly testing something extremely voltage sensitive then its not the meter for you. I've never damaged anything but I'm sure if somebody has you'll hear about it.
Title: Re: Five volts on DMM diode checks, is it an issue for concern?
Post by: janoc on July 07, 2016, 10:36:29 pm
Deciding whether to purchase a Keysight 34461A or a Fluke 8845. Both employ five volt sourcing on diode checks.

There has been some concerns expressed about the use of five volts and potential damage to certain components, yet, at least two major high end manufacturers have moved to the higher five volt parameter.

Something I should consider in my purchase?

It is very low current, usually on the order of an 1mA. You are not likely to damage anything with that, even if the component you were testing had a lower breakdown voltage. The higher voltage is needed, otherwise the meter would have problems with LEDs - especially white and blue ones that have 3+ volts forward voltage.

On the other hand, that's why humans come equipped with a bulbous hairy protrusion at one extremity of their bodies - to use the brain inside it before using the probes of the meter. If you are testing something super sensitive, then don't use diode check mode, it is that simple.