Does anyone know if either side of the primary coil of a NST is connected to the core? I know that the center tap of the secondary coil is connected to the core. The reason I am asking is that I measured the resistance between the hot lead of the primary coil input to the ground lug of the NST and measured 582 ohms. I also measured the resistance of the neutral lead of the primary coil input and also measured 582 ohms. I didn't expect this. I expected a very large resistance, practically infinite ideally. Perhaps this is a NST about to fail. I have been operating it without the center tap connected to ground which I will now correct. The transformer in question is made by Jefferson Electric and is a 15 KV, 60 ma model. It is an old-fashioned unit with no GFIC.

I measured another NST and got a resistance of 208K ohms. Still less than I expected but much better. This one is also an old fashioned unit without GFIC.

Has anyone had any experience with the 1.5 volt lithium-ion rechargeable batteries? One consists of a normal 3.7 volt li-ion battery with a built-in buck converter to bring the voltage down to 1.5 volts. The primary operational difference from a conventional battery is that the output drops abruptly to zero when the battery is fully discharged.

I have been experimenting with the AAA size. One has failed completely. It seems to me that there must be a small constant drain on the battery even when not connected due to the buck converter drawing some small amount of power in the quiescent state. Does anyone know?

I thought the forum would find this interesting. I have always wondered what the ECU (engine control unit) for a car looked like. Our 2006 Dodge Charger recently needed a new ECU. I bought a salvage-yard unit and replaced the defective one.
I disassembled the old unit to see what was in there. It was tough because the the thing is glued together like an iPhone but I eventually got it apart. I actually had a fantasy of finding a defective solder joint and repairing it. 😂

Take a look at the ECU circuit board, and this is just one side. There are hundreds if not thousands of small-pitch solder joints! I took a quick look with a magnifier and couldn't see anything obvious. Everything is also potted so soldering would be difficult at best even if you found a bad solder joint. Forget about repairing one of these yourself! There are companies that claim to be able to repair these. I don't see how they do it.

I have an old KLH R3100 receiver which has recently developed a 60 hz hum in both speakers. It does it for all inputs. I have tried all sorts of grounding ideas to no avail. The amp has worked perfectly for about 10 years. It just recently developed the 60 hum. Are there any ideas as to the problem? My initial thought was that perhaps a capacitor has failed.

I could just buy another old used receiver on Craigslist for $50 but if this one can be easily repaired I would rather just fix this one.

I use a SMPS to power my voltage multiplier (VM). The VM uses a ZVS driver and two AC flyback transformers as the HV supply. Power input to the VM from the SMPS is 250 - 300 watts. The SMPS supplies 30 volts at 10 amps. I've noticed that the SMPS will occasionally shut down when the VM is discharging into its resistive load. I suspect its because the ZVS driver is causing current spikes in the SMPS output.

I have a 50,000 uF 40 volt electrolytic capacitor laying around. I was thinking of connecting this capacitor in parallel to the SMPS output in order to reduce any ripple in the SMPS output being caused by the multiplier ZVS driver. The power would be applied gradually until the capacitor charges to at least 12 volts before switching on the VM to avoid killing the ZVS MOSFETs. Does this sound like it will work?

As some of you may know I have a small high voltage Youtube channel. Overnight one of my videos went from 606 views to over 1000 views! Granted, this is my coin shrinking video which is particularly interesting IMHO but normally this video would only gain a few views per day. None of the other videos were so affected. This seems very unusual to me. Has this happened to anyone else with a Youtube channel? Does this seem legitimate?

My only explanation is the link got shared with some big group and a lot of people in that group suddenly viewed it. I've heard of coordinated campaigns to bombard certain channels with "Dislikes" but I've never heard of bombarding a video with views. That wouldn't make any sense.

I'm not complaining, just wanting to understand where the big surge came from or if it was some sort of nefarious activity.

Has anyone done any experiments or demos using a capacitor bank to "explode" water? I want to use my pulsed power generator to do this. I'm hoping to use a few teaspoons of water to blast a large hole in a piece of 3/4 inch plywood as a demo.

I have a pulsed power generator used for several things such as coin shrinking. I can shrink a quarter to the size of a dime with about 7000 joules.

Shrinking coins is a compromise between coupling, resonant frequency, and energy level. My current work coil consists of 10 turns of 13 AWG magnet wire. This was arrived at after a lot of experimentation. This combination works well for shrinking a quarter to dime-size. However adding more energy does not provide any further shrinkage due to the work coil exploding before the peak power level is reached.

I now want to make a "ball quarter". I have attached an image of one. I know that a more robust work coil that can hold together longer is needed, though it will still be sacrificial. And of coarse more energy is also needed. Its not as simple as just using larger AWG wire because the coil gets longer and reduces coupling.

I don't know the details of how the ball quarter in the picture was made. I heard that flat ribbon magnet wire was used wound "the hard way". Its unknown how much energy was used. I have available up to 24,000 joules which I think is plenty.

I don't want to make that difficult ribbon wire coil though. I had another idea which now brings me to the subject of this posting.

My idea is to closely surround one of my current 10-turn 13 AWG work coils with a solid block of G10. My thinking is that this may hold the work coil together long enough to make the ball quarter. G10 is the only non-conductive material that I can think of that has a chance of withstanding the expansive force of the work coil moving outwards.

Any thoughts are appreciated.

This is the load resistance and discharge terminal for my 14-stage CW voltage multiplier. The multiplier was discussed in a previous posting. The specifications are as follows:

* Resistance is 6.8M ohms
* Voltage rating is 400K volts
* Power handling capability is 300 watts

I designed this load to operate in air rather than oil. Here is a link to a video explaining the design challenges.

Today was so nice outside I opened up my shop door. From outside you can see how crammed it is with projects and tools. Its actually less crowded when you get inside.