The mains side of the power supply section is double insulated. The problem comes about if the test leads are connected to a dangerous voltage, since even if the switch had been soldered correctly, the gap from the terminal to the body is dangerously small, IMO.
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He specifically says he buys by looks first. Not an engineer yet.
Metaphorically... I want a BMW on the outside and a BMW on the inside. (I don't think much aerodynamics where traded off for better looks.) But since the speed limit is 60km and I'm not rich, I'm ok with less under the hood. Pop in some mass produced asian engine and I'll be ok.
iows..I'm after the stylish DMMs without crappy guts.. If there are none, then I'll settle for ugly on the outside with performance guts. I'm looking at tradeoffs.
"D from BC" schrieb im Newsbeitrag news:MPG.25d4067bce59ab63989686@209.197.12.12...
You are a lady aren't you? Ban Apricale, Italy
Mike Warren wibbled on Thursday 04 February 2010 02:55
Yes, exactly. The machine is designed to be exposed to dangerous voltages, possibly with an earth reference, so double insulating the PSU isn't good enough cause to not earth the extraneous metalwork IMHO.
I'm an absolute amateur WRT electronics (I "do" linux, and a bit of electronics as a hobby). I've always earthed metalwork on any mains stuff I've knocked up, no matter how well insulated the live parts may be.
Can't help feeling that they perhaps should have fully isolated the measurement circuits from the computer interface (optically or magnetically), but then people always moan I overegg everything ;->
D from BC wrote in news:MPG.25d4067bce59ab63989686@209.197.12.12:
Why is HP34401A "cheap crap"? I had one while at TEK,and it was a great meter.
If it's "cheap crap",then what is a good 6.5 digit meter? And HOW?
Everything is isolated. The only possible place for a failure was on the AC/DC switch, which by necessity is electrically connected to the test probe side of the meter. They should had used a switch designed for isolation, or perhaps a plastic lever so the case would not be connected to the outside world.
Mike Warren wibbled on Friday 05 February 2010 01:17
Or even an insulated panel ;->
Yeah - that does look like the same cheap switch that was in my HeathKit alarm clock kit 30 years back :)
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