Why is it I see so many people raving about analog insulation resistance testers? Why do those using them believe they are so superior and for what reason? Or are there any links or rescorces to read up on?
Appreciate any information
Analog vs Digital Insulation Resistance Testers
Re: Analog vs Digital Insulation Resistance Testers
I have both types.
Also an older hand-cranked analogue, now only for workshop use.
"Horses for courses."
If I want to record test values - which isn't often, 'cos it slows you down - I might use the digital;
because it's easier to read the digits than to read off a scale.
But I prefer my analogue IR tester for most situations - both for IR and for earth continuity.
Two main reasons:
- It's quicker - the digital takes a lot longer to provide a reading; and when you have a lot if readings to take, that matters
- It shows a trend - rising or falling - while often all the digital shows is a blur of numbers
In my case it's also smaller, and so easier to lug around;
plus the "test" button is conveniently placed for activation by left thumb; while holding the case in left hand, and applying other probe using right hand to various items requiring to be tested. For earth testing, left hand will also be holding trailing lead.
True the digital appears to give a more "precise" reading; but we seldom need that sort of precision.
We generally don't care what the actual reading is, as long as it's on the right side of the "pass / fail" mark.
So the extra "precision" is largely wasted - bearing in mind that only the first digit matters while the second can't be trusted at all.
Meaning we never get the sort of precision that all digital meters seem to offer.
For IR tests, any reading that isn't well above the pass mark should be treated with suspicion.
For earth continuity - and the low-range of an IR tester is the only thing we should use for that - we need to apply meter error.
With analogue, once you're used to the meter it's easy to know how much the reading error (% of full scale deflection for true analogue) amounts to (always the same value, but occupying different length on different parts of the scale); so all we have to do is see the needle that much above the "mark" and all's good.
With digital (including electronic analogue), every reading requires a mental calculation for both percentage-of-reading and then the number-of-digits value has to be applied. Digital (and electronic analogue) are not constant; but we can work them out for digital readings that appear to be close to "pass"; and mentally adjust the "pass" mark accordingly. Remembering that the same correction can't be used for widely different readings.
When a truly precise reading is required, regardless of digital / analogue; a calculation has to be done; which will put the reported / recorded value into a range above and below the raw reading. Plus of course a reference test against a known "test" resistance; before we even start.
Also an older hand-cranked analogue, now only for workshop use.
"Horses for courses."
If I want to record test values - which isn't often, 'cos it slows you down - I might use the digital;
because it's easier to read the digits than to read off a scale.
But I prefer my analogue IR tester for most situations - both for IR and for earth continuity.
Two main reasons:
- It's quicker - the digital takes a lot longer to provide a reading; and when you have a lot if readings to take, that matters
- It shows a trend - rising or falling - while often all the digital shows is a blur of numbers
In my case it's also smaller, and so easier to lug around;
plus the "test" button is conveniently placed for activation by left thumb; while holding the case in left hand, and applying other probe using right hand to various items requiring to be tested. For earth testing, left hand will also be holding trailing lead.
True the digital appears to give a more "precise" reading; but we seldom need that sort of precision.
We generally don't care what the actual reading is, as long as it's on the right side of the "pass / fail" mark.
So the extra "precision" is largely wasted - bearing in mind that only the first digit matters while the second can't be trusted at all.
Meaning we never get the sort of precision that all digital meters seem to offer.
For IR tests, any reading that isn't well above the pass mark should be treated with suspicion.
For earth continuity - and the low-range of an IR tester is the only thing we should use for that - we need to apply meter error.
With analogue, once you're used to the meter it's easy to know how much the reading error (% of full scale deflection for true analogue) amounts to (always the same value, but occupying different length on different parts of the scale); so all we have to do is see the needle that much above the "mark" and all's good.
With digital (including electronic analogue), every reading requires a mental calculation for both percentage-of-reading and then the number-of-digits value has to be applied. Digital (and electronic analogue) are not constant; but we can work them out for digital readings that appear to be close to "pass"; and mentally adjust the "pass" mark accordingly. Remembering that the same correction can't be used for widely different readings.
When a truly precise reading is required, regardless of digital / analogue; a calculation has to be done; which will put the reported / recorded value into a range above and below the raw reading. Plus of course a reference test against a known "test" resistance; before we even start.
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