NO, I did Amps and milliamps and figured if I couldn't see any milliamps ... why would I go fishing for microamps? Just didn't make sense at the time ...
And of course, because you brought it up, I went and checked also for microamps on the AC setting and I got ZIP! Yet when I switch to AC voltage and put the terminal back into the voltage port I still get a solid 6 volts
what confuses me is that psu's usually couple the output negative to the rectified side of the input.
so you shouldnt see a 60Hz wave.
at worst you should see a 100Hz rectified sine with lots of dampening from the primary cap!
Really doesn't matter if it's AC or not, just matters how much absolute current can pass through. Ideally that capacitor is small enough (in capacitance) that no more than 1mA will pass through or so, with any "proper" AC voltage presented at the input.
If you plug it into a GFCI outlet, short the case of the laptop to ground, and it trips, then you know you have a problem...
what confuses me is that psu's usually couple the output negative to the rectified side of the input.
so you shouldnt see a 60Hz wave.
at worst you should see a 100Hz rectified sine with lots of dampening from the primary cap!
Really doesn't matter if it's AC or not, just matters how much absolute current can pass through. Ideally that capacitor is small enough (in capacitance) that no more than 1mA will pass through or so, with any "proper" AC voltage presented at the input.
If you plug it into a GFCI outlet, short the case of the laptop to ground, and it trips, then you know you have a problem...
Is there ANY risk of damage to the laptop doing that?
Is there ANY risk of damage to the laptop doing that?
Nope, you're just taking the stray voltage and sending it where it should've been in the first place.
Don't buy those $10 PSU "specials". They fail, and they have taken whole computers with them.
My computer doubles as a space heater.
Permanently Retired Systems:
RIP Advantech UNO-3072LA (2008-2021) - Decommissioned and taken out of service permanently due to lack of software support for it. Not very likely to ever be recommissioned again.
Asus Q550LF (Old main laptop, 2014-2022) - Decommissioned and stripped due to a myriad of problems, the main battery bloating being the final nail in the coffin.
Kooky and Kool Systems
- 1996 Power Macintosh 7200/120 + PC Compatibility Card - Under Restoration
- 1993 Gateway 2000 80486DX/50 - Fully Operational/WIP
- 2004 Athlon 64 Retro Gaming System - Indefinitely Parked
- Main Workstation - Fully operational!
Well it's normal to see a 50Hz or 60Hz backgroud due to the house wiring.
Just so you don't confuse yourself you might want to watch this video. https://www.youtube.com/watch?v=yKb7xIsPjVM
The filter that stj mentions is present in all hand held meters.
But a scope will not have it, and this picks this noise up, same for a high-end bench dmm.
"The one who says it cannot be done should never interrupt the one who is doing it."
Well it's normal to see a 50Hz or 60Hz backgroud due to the house wiring.
Just so you don't confuse yourself you might want to watch this video. https://www.youtube.com/watch?v=yKb7xIsPjVM
The filter that stj mentions is present in all hand held meters.
But a scope will not have it, and this picks this noise up, same for a high-end bench dmm.
Thank you for that video. It makes perfect sense. But I'm not sure how this phenomenon applies to my readings when I have the meter on current reading vs. voltage reading. As we saw, the voltage reading was consistent between the Fluke meter and the oscilloscope ... and I can't take a current reading with the scope to demonstrate that the ZERO reading I was getting from the Fluke was due to the fact that it averages the reading over one power cycle...
However, I suppose it stands to reason, that where there is voltage, there has to be current ... and where the Fluke reads 6 volts yet 0 amps even at the microamp level ... I suppose this explanation is as good as any ... the other explanation could be that the actual amperage is less than one microamp.
An update on the original topic here ... I purchased this power cord for my MBP power brick and it has a spring-loaded flat piece of metal that grabs onto the metal disc that protrudes from the charger and I verified that the metal is connected to the ground pin on the plug. When I connected it to my charger and plugged it in, the vibration that I was getting from the chassis is now gone ... so it appears that the only way to properly ground a mac book charger is by purchasing one of these cables.
When I connected it to my charger and plugged it in, the vibration that I was getting from the chassis is now gone ... so it appears that the only way to properly ground a mac book charger is by purchasing one of these cables.
Yes, you're returning the Y-cap leakage thru the EGC; the case (and V-) are now at GND potential. Or thru a resistor of 10-1000 ohms.
Measure the resistance from the case to the line plug's ground pin with a DMM!
"pokemon go... to hell!"
EOL it...
Originally posted by shango066
All style and no substance.
Originally posted by smashstuff30
guilty,guilty,guilty,guilty! guilty of being cheap-made!
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