30-04-2012, 06:55 PM
Hi Joe.
I don't know how much that VTVM cost you - and I don't need to know - but in my opinion, these days a VTVM is a rather under-rated item of test kit. Agreed, modern technology has given us DMMs that do a similar job - primarily measurement of voltages with minimal loading on the cct. under test, but a VTVM is always useful as a device to confirm that reading and unlike a DMM, will usually enable measurements up to several MHz - with a diode detector. (And if it's mains-powered, you don't have to worry about flat batteries!
) Plus, of course, VTVMs are a lot easier to repair and aren't as prone to giving misleading indications as modern DMMs can do. Of course, if a 'scope is to hand, then that will tell you everything that a VTVM will, but not everyone owns a 'scope, and even then a VTVM is usually a good deal smaller that a 'scope (thinking of the ever-shrinking bench-top space.) And then again, there are some maintenance procedures that specifically call for a VTVM to be used: the handbook for the Racal RA-17 springs to mind.
I look forward to the pictures that you say you'll upload.
Al.
I don't know how much that VTVM cost you - and I don't need to know - but in my opinion, these days a VTVM is a rather under-rated item of test kit. Agreed, modern technology has given us DMMs that do a similar job - primarily measurement of voltages with minimal loading on the cct. under test, but a VTVM is always useful as a device to confirm that reading and unlike a DMM, will usually enable measurements up to several MHz - with a diode detector. (And if it's mains-powered, you don't have to worry about flat batteries!
) Plus, of course, VTVMs are a lot easier to repair and aren't as prone to giving misleading indications as modern DMMs can do. Of course, if a 'scope is to hand, then that will tell you everything that a VTVM will, but not everyone owns a 'scope, and even then a VTVM is usually a good deal smaller that a 'scope (thinking of the ever-shrinking bench-top space.) And then again, there are some maintenance procedures that specifically call for a VTVM to be used: the handbook for the Racal RA-17 springs to mind. I look forward to the pictures that you say you'll upload.
Al.
