They do cycle test indeed on that brymen's.
No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
I've seen the video where you test pocket meters and the uni-t stood better What about a lifecycle on that little switch? I've seen a new pocket meter aneng 302 which has EF, true rms on Voltlog channel .. and of course basic input protection...
I can see you are one of the UNI-T pocket meter believers! You are not alone.
I test with VERY low energy levels. 20J max. It's nothing. Now again, keep in mind that the energy available is NORMALLY not dissipated in the meter. Where's it go? It's dissipated internal to the generator in the coupling network. It's not just a bank of caps and a switch like some people have posted. These people are lost. The only time a meter would dissipate anything is if it breaks down. Obviously, some amount will be dissipated in the clamping network (assuming the meter has such a clamp) but this is not what I am referring to. I'm basically describing a short. This is when you get to see in some of Fluke's videos where the meters explode.
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Let me add also that people have posted how I am slowly damaging the MOVs and how running them at high voltages will degrade them with time. Again, it's not the case. Sure the MOVs will degrade but for fun I setup a long term test showing the currents through a meter as I pushed the input voltage far past the meter's rating. People seem to think the MOVs take the direct hit, which in all of the meters I have looked at, that's certainly not the case. The MOVs sit behind a series of resistors and PTCs which limits the current available to them. When I mention above that some energy is dissipated in the clamp, this is divided across all of those components, not just the MOVs. And when we consider most meters will use the standard 1K resistor in series with a 1.2K PTC and a 1.5KV MOV, not much is dissipated. It won't suck down that 20J available.
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In my testing, when a meter does break down, there is not enough energy available to the meter to do much of anything. Make a few sparks, maybe blow apart a capacitor or an IC at best.
So we have a UNI-T that does not have near enough clearances and breaks down. The generator does not provide enough energy to do anything more than make a small spark. The breakdown voltage is low enough that the meter is basically undamaged. Now, IMO, that it not a good thing. The UT90A is like that and its why it continues to stay in my box of tricks. If my generator had more energy, these meters would ... well.. I guess I'm not sure what would happen but I would like to see it, on the other side of a safety glass case.
I'm sure you have seen my other generator that I refer to as a half cycle line simulator. Unlike the fast, high voltage, low energy transient generators I normally use to run these test, this one creates a slow, low voltage, higher energy transient. I've shown where this generator has no effect on the better class of meters. Why? Because they do not break down. And without a low impedance path, nothing is going to happen. I don't use that generator to collect any data from the meters I look at. There is no mention of it in the spreadsheet. It's more just to give the viewers some idea of what could happen if a meter were to breakdown.
In this video, I attempted to finish off the UNI-T UT90A with it. Again the poorly designed layout saves the meter's electronics. Don't mistake this for being a robust meter. It's not!
https://youtu.be/VHZ5cQPGo64?t=484You can see, I normally run this test with the meters set to their highest AC voltage mode. Here's the free HF meter. Again, if this meter had not broke down, nothing would have happened.
https://youtu.be/GHWb0kjrIY0?t=72