High Voltage Ground

I'm starting to work with high voltages again, but for real this time. I just built an ignition coil driver, using a 555 (and I got an ignition coil), but my 555 broke (the texas instruments ones can only drive 15mA, oppose to the normal 200mA, oops) so I have to go buy one today. My main question is what to use for ground, whether it be for an old screwdriver for arcing sparks or the secondary of a tesla coil. I was originall just going to use the 3rd prong of an outlet, but somewhere on the internet I heard this could destroy all surge protected power strips and destroy all plugged in electronics at your house. I, of course, do not want this cause... well... I'd be screwed. Is this true or not? Can I use the 3rd prong?

Topic by guyfrom7up   |  last reply


Electronic repair after a voltage spike or power surge

So far I was lucky and never got a lightning strike or other power failure to induce high voltages into my house and equippment. But over the time I got several requests from friends to take a look at things after literally all connected electronics in their house got fried. In some cases there is only a total write off as due to a lack of surge protectors inside all unwanted juice made it's way into vital components. Like a brand new Samsung TV where the replacement of the power board was the only option - which makes you wonder... But in other cases, like microwaves, induction cooktops, computers and such I had some good success with the repairs. Guess it comes down to purs luck on both sides, power surge was not too bad and simple components on the input side failed quickly enough to prevent damage to microprocessors or other sensitive parts. Right now I have an induction cooktop here again that failed after a mains transformer in street blew up during a thunderstorm. I can tell it was bad as everything in the area of fried parts has a vaporizsed metal film on the surface and not much is left that was a surge protection. I cleaned all up, replaced the varistors and missing parts of the traces on the circuit board but the cooktop is not performing the way it should anymore :( At some stage during cooking it turns off with a meaningless error code stating the input voltage was out of bounds. So my next attempt was to literally remove every single component from the filter and power supply board to measure for any possible connections between the traces. By doing so I noticed several points where I had a quite high but measurable resistance in areas where there should be none. Mostly on the direct input side where the varistors tried to save things. So I used my Dremel in a tin drill press to cut the circuit board aourd the affect areas (where possible with a drill, otherwise with a thin grinding disk).. Sure enough I was greeted by charcoal colored dust in several areas. After removing all material until the dust was "clean"  tried again and this time all seems to work fine. I would like to use this topic to offer some help and guidance in case you have devices that suffered a severe power surge of some sort. Many of us either have no insurance to replace those items or even if you do the device might be expensive enough to try a repair despite getting it replaced. Trust me, even it went up in smoke there is still a chance to fix it in some cases and if proper protective circuits were in place the repair could as cheap as a few Dollars for replacement parts. To get useful advice the following things should be included in your request: Some clear pictures showing a close up of the affected parts - if there is visibale damage to be seen. A brief description of what happened, e.g.: lightning strike directly into the house or outside power lines, generator or inverter failure or simply that the power company stuffed up and your entire street was affected. Of course you will need the means to take the device apart for investigation and also some basic soldering skills or somehow how has and can assist you. But if you are up to the challange I am willing to help if possible.

Topic by Downunder35m   |  last reply


Voltage Stabilizer Efficiency Loss (Extra power consumption)

Hello All, I am using an 1KVA Voltage stabilizer for my Fridge. The power quality is really poor here in India, and these things are mandatory. I learnt the lesson hard way :-(.... Well that aside, i would like to know what would be the power loss or Extra consumption these devices use when regulating power. Actually,i could use a general lecture on how Stabilizers work!

Topic by bhvm   |  last reply


Convert 320VDC to 230VAC or 48VDC voltage using 230VAC (UK) UPS?

I've got access to 12 flexible Solar Panels - 320VDC each I live in the UK where mains voltage is 230VAC and also might buy an electric engine which would run at 48VDC. Would a UK voltage (230VAC) UPS be able to step down the 320VDC to either 230VAC or 48VDC for use on a boat? I'm thinking I could connect 12 panels in parallel and use either; Double-conversion UPS to deliver 48V by bypassing the conversion from the battery back to 230V or  Line-interactive UPS to deliver 230V directly from the 320VDC. The question is would the UPS's surge protection be able to deal with the high voltages? (Keeping in mind the sun isn't real bright in the UK). Also with regard efficiency will there be a lot of power loss in the system? I don't really know how surge protection from overvoltage works in UPS's and assume it uses some kind of buck conversion...? I'm guessing that the surge protection circuits might struggle with continued voltage overload. Does anyone know if this would be the case? The question is, will the UPS's be able to reliably deliver either 230VAC or 48VDC? Here are the specs for each individual panel; http://www.innoasia.net/2010/pdf/presentation/SmartCity_Takano.pdf Open circuit voltage(Voc): 429V Optimum power voltage(VMP):319 V Short circuit current(Isc): 0.39A Max operating current(IMP): 0.288A torrence:+_5% Maximum system voltage: 1000V THERMAL CHARACTERISTICS: (-25 ° C to +90 ° C) Temperature coefficient É‘Isc +0.08%/ ° C Temperature coefficient É‘Voc -0.35%/ ° C. Temperature coefficient É‘Pmax -0.15% / ° C. Over-current Protection 30mA

Question by mchin2   |  last reply


Joule Thief. I know how they work, but is a joule thief self-regulating and self-limiting? Is a varying input (DC) okay?

Joule Thieves. I know how they work (my one works fine) , but is a joule thief self-regulating and self-limiting? Could I hook it up to a 12V source? Is a varying input voltage okay? -- Will the voltage/current across my white LED (should be 2.6VDC absolute max) be too high or surge? I would like to know if it would be suitable to use on my motorcycle to drive an additional LED or two for a headlight supplement. The voltage varies between 11.5VDC and 18.2VDC. I have a basic handmade circuit, with a hand-wound toroid and a generic transistor, usually running from a stable 1.1 to 1.6VDC, I have tried it with a 9V cell and it seems to work alright, but I want to be sure before modifying it/or my motorbike. Any help much appreciated! 8-)

Question by xerxesx20   |  last reply


LED indicator

How should I drive an LED from a 38 volts power supply? The led wizard says I need a 1800 ohm, 2 watt resistor, but it also says' it'll disipate excessive heat. I recently took apart a surge protector and found that they drive an LED from a 120volt source by having a diode, LED and what appears to be either a 1 or 2 watt resistor. I need help driving an LED from a 38 volts power supply just as an indicator.

Topic by guyfrom7up   |  last reply


Power strip measures energy use, costs much more than separate power strip and monitor

Again, anyone want to collaborate to make our own? This thing Cut down on energy costs and reduce your electric bill. Simply plug the easy-to-use Power Cost Controller with surge protection into the wall and connect your electronics to the power strip to see how efficient it really is. Large LCD display will count consumption and cost by the kilowatt-hour, same as your local utility. Monitor your electric consumption by hour, day, week, month, even an entire year. Also check the quality of your power by monitoring voltage, line frequency, and power factor. Measures 8-1800W appliances. Now you'll know how much your computer network or home media center really costs! Replaceable 1.5V battery included.

Topic by laminterious   |  last reply


follow-up capacitor Q's ? Answered

I am amazed at all the great responses I got with my last question, thank you all! :D Though now I have a few more: 7) Should I try to learn how to work with complex impedance (capacitors, resistors, and inductors in all sorts of weird configurations) Also, can I treat reactance in general as a resistance when looking at capacitors in series or parallel with resistive loads and stuff? For example, can I simply add up Xc, Xi, and R for a total impedance? Or do I have to worry about phase shifts and stuff?  8) Is it OK to say that "Q" or charge is a more theoretical physics concept and is not too important with practical electronics? (C, V, and I being more of the focus and "ignoring" Q is OK?) 9) I have added a few of the "slides" and sneak-peaks to my upcoming video. If anything is wrong don't hesitate to nitpick and point it out! 10) capacitor fall under 2 major categories, polarized and nonpolarized. 10a) [under the 'polarized' branch] Electrolytic and tantalum capacitors are used for bulk filtering, but are evil and do not tolerate overloads particularly well. Especially tantalums. They tend to be available in huge capacitances, but can be "leaky" and have high ESR and series inductance. 10b) [under nonpolarized branch] Ceramic capacitors are the most common type of capacitors, and come in a few types. Generally used for local decoupling. They are pretty robust and tolerate overloads. Film capacitors find more use in high voltage applications, have lower leakage, better high frequency performance, and certain types have self-healing properties allowing them to tolerate overloads and surges the best. Mica capacitors are generally the most stable, with the lowest leakages, so they find uses for more critical analog applications.

Question by -max-   |  last reply