When I was assessing surge protection for a RF output on a signal generator (in case it accidentally connected to a significant voltage), I found when measuring a MOV with a capacitance meter, it shows that MOVs can have significant capacitance, whereas gas arrestors have very little capacitance, of which some types in a catalog had a capacitance of about 1pF, which is ideal for most RF applications.
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My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics. -
Re: MOVs can have capacitance
If you look at the MOV spec, it will show the capacitance rating. Gas tube will be the way to go, but to find one at 1pF may be difficult.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809 -
Re: MOVs can have capacitance
Some low surge power ESD diodes can have sub 0.1pF capacitance, for example for HDMI transceivers. I wouldn't know if it is possible to make similar diodes for high surge power.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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I have a whole home surge protector (Eaton CHSPT2SURGE). This is the lower end model as compared to the CHSPT2ULTRA. When I took it apart, I noticed it's basically the same PCB as the higher end model, just missing the extra MOVs for higher capacity. Coincidentally, I have a pack of brand new Bourns 20D241K MOVs laying around:
https://www.digikey.ca/en/products/d...0D241K/2799098
The only thing I noticed is that these Bourns MOVs are not thermally protected with a fuse. I'm wondering if it's safe to just simply install these extra MOVs for extra capacity,... -
I know most people would just buy a new one at the store. But hey... this is Badcaps afterall, right?
For quite some time I've had the crazy and naive notion that surge protectors just worked, and lasted forever
I have been occasionally buying new units because you can't really tell how many joules are left in the MOVs after a few power surges. Some units I have had for 10 years and surely their MOVs are toast by now. Instead of buying new ones and funneling money over to china, I thought about just replacing the MOVs in the existing ones I have. All of the plugs still...
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I'm finally recapping my Soyo K7VX6 motherboard (aka KT600 Dragon Ultra) and replacing Sacon SZ-series caps. The Sacon SZ datasheet provides a spec for tan delta, but not for ESR, while the candidate replacement caps are specified in terms of ESR.
I found this nice little description of the conversion:
Calculating capacitor ESR from Tan(delta)
https://forum.digikey.com/t/calculat...-from-tan/2633
It mentions that a general spec for tan delta has to be adjusted for the specific capacitance before plugging tan delta into the formula... -
Howdy folks,
I have an Optiplex GX260 that blew a couple of those troublesome Nichicon HM series (ultra low ESR) electrolytic capacitors. Because said caps are obsolete, they are pretty much impossible to find on the market; I did find a listing for some but I believe they are counterfeit. I feel the easiest thing to do would be to replace all the blown caps with polymer ones. I am by no means an expert in electronics, and I've found a fair bit of conflicting information, so any guidance or confirmation would be greatly appreciated. While from a practical standpoint it's not worth... -
Hi everyone,
Recently I acquired a treadmill that was hit by a power surge (I assume). On the control board, there was a varistor that was blown apart and two traces that were partially blown out. I replaced the varistor (to my knowledge it is a matching one) and wired back where the traces were with some 22 awg solid copper wire. When I went to power it on, still nothing. On a quick inspection with my meter, I was getting incoming voltage on the AC in terminal.
The board is a MC2100LS-30 treadmill controller.
Visibly, there are no other problems....
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