PV MOSFET driver reliability

Started by Piotr Wyderski in sci.electronics.design8 years ago 42 replies

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only...

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only during exceptional scenarios), which implies constantly energized LED inside the coupler. For many^2 years. Is it an obvious no-go? One alternative is a transformer-coupled full wave rectifier driven by an oscillator I already have. Seems to be bul...


high voltage supply breadboard

Started by John Larkin in sci.electronics.design7 years ago 39 replies

I posted my C-W HV supply circuit somewhere above. I don't entirely trust my Spice model. The models for the 2SK4177 and MMBD5004 are iffy,...

I posted my C-W HV supply circuit somewhere above. I don't entirely trust my Spice model. The models for the 2SK4177 and MMBD5004 are iffy, and I've been simulating with zero leakage inductance in the transformer, because adding it slows down the sim radically. It's raining, so I can't stain the deck, so I hacked a breadboard. https://dl.dropboxusercontent.com/u/53724080/Circuits/HV/HV_...


A stupid question about Sine Generator in Spice/LTSpice

Started by M Philbrook in sci.electronics.design6 years ago 25 replies

I find it annoying that I can't simply set the starting degree angle I want without it causing an offset, unless I do 0. Currently I...

I find it annoying that I can't simply set the starting degree angle I want without it causing an offset, unless I do 0. Currently I get around this using the delay parameter and the sine will start with the correct offset so that it crosses the axes properly. I was doing a 3 phase transformer simulation the otherday and needed to do Delta, WYE etc, connections. Using DC offse...


Camping Electric Fence as a Bear Deterrent

Started by Anonymous in sci.electronics.design6 years ago 28 replies

I hope this system could be used overnight when camping in forests with bears and be powered by batteries. The wire perimeter could be attached to...

I hope this system could be used overnight when camping in forests with bears and be powered by batteries. The wire perimeter could be attached to trees with fence staples and a turnbuckle could be used to tighten the wires. A inverter circuit with ferrite transformers could be used to initially step-up the voltage from 12V DC to 120V AC with a 10:1 transformer and then another tran


Rewiinding a MOT

Started by amdx in sci.electronics.design2 years ago 69 replies

I thought I could remove the secondary and the shunts, then install a new secondary and have a low voltage transformer, maybe not. I removed...

I thought I could remove the secondary and the shunts, then install a new secondary and have a low voltage transformer, maybe not. I removed the HV secondary, Then wound 10 turns and got 8 volts. I loaded it with 2 ohms, all is well except the PF is 0.15. I will need to have about 25 turns to get my 20 Volts, but, do I need to do something about the PF? Why is it so low? I expect Ph...


PRBS in LT Spice

Started by John Larkin in sci.electronics.design10 years ago 25 replies

We are considering sending data over CAT6 twisted-pairs, from one FPGA to another at some 10s of meters distance. It might be prudent...

We are considering sending data over CAT6 twisted-pairs, from one FPGA to another at some 10s of meters distance. It might be prudent to transformer-couple the data, to avoid ground-loop common-mode hazards, and the obvious choice would be to use RJ45 connectors with built-in Ethernet magnetics. These seem to have inductance in the 400 uH range, which gives a low-end frequency response in t...


klunky pc board

Started by Anonymous in sci.electronics.design3 years ago

https://www.dropbox.com/s/20fepk4db4rfkd2/P903_Range_Switch.jpg?raw=1 This accepts four transformer secondaries on the left, faston...

https://www.dropbox.com/s/20fepk4db4rfkd2/P903_Range_Switch.jpg?raw=1 This accepts four transformer secondaries on the left, faston tabs, and switches the windings with relays, in four combinations of series and parallel. Output is on the right, both fastons and a pluggable Phoenix. There's an isolated delta-sigma ADC, with a dc/dc converter, to snoop the final output voltage. 4 layers,...


Where Did It Go? EMF Cancellation Within a Toroid

Started by Robert Miller in sci.electronics.design5 years ago 3 replies

I have a toroidal transformer with split primary windings. If I connect the two windings so their fields oppose, and apply an identical signal...

I have a toroidal transformer with split primary windings. If I connect the two windings so their fields oppose, and apply an identical signal to each, I presume that due to the properties of a toroid there is no EMF emitted. Yet it appears current is still being consumed. Silly question: If there is no magnetic field being produced, where is the energy going? If there is a magnet...


12v to 300v @ 1200W

Started by Yzordderrex in sci.electronics.design8 years ago 18 replies

I may need to do a 12vdc to 300vdc converter good for 3 amps. I'm guessing= near 1200w on the input side when efficiency taken in. I'm...

I may need to do a 12vdc to 300vdc converter good for 3 amps. I'm guessing= near 1200w on the input side when efficiency taken in. I'm thinking push-pull or half-bridge. =20 I'm leaning towards the half-bridge because it will make transformer easier= to construct. I might be able to use one turn of copper or the primary and= probably 55 or so turns on the secondary. Maybe some SiC sc...


Laminating Mu Metal Core

Started by Robert Miller in sci.electronics.design6 years ago 35 replies

I need to produce a flat transformer core by laminating together 12 thin Mu metal strips, each 10mm wide and 50cm long. What is best practice...

I need to produce a flat transformer core by laminating together 12 thin Mu metal strips, each 10mm wide and 50cm long. What is best practice to minimize movement and eddy currents? I have heard the laminations should be electrically insulated from each other and glued together to form a solid unit. But, in practical terms, how is this done and what materials are used? It seems to ...


Low cost mains power supply

Started by Nomen Nescio in sci.electronics.design9 years ago 10 replies

In most DIY stores you can find these cheap Chinese digital timers to turn you lamps or appliances on at specified time. The thing I'm wondering...

In most DIY stores you can find these cheap Chinese digital timers to turn you lamps or appliances on at specified time. The thing I'm wondering is, how do they power the digital circuitry from 110VAC in a device costing only $5-$10? Are they using a transformer or are they directly powering the digital circuitry from the AC voltage?


Si contact I-V

Started by George Herold in sci.electronics.design9 years ago 7 replies

Hi all, So I=92m trying to make contacts with indium to a hunk of Silicon = that I have. Seemed OK Resistance between contacts of ~400 ohms....

Hi all, So I=92m trying to make contacts with indium to a hunk of Silicon = that I have. Seemed OK Resistance between contacts of ~400 ohms. =20 I then did the I-V, Signal generator (100Hz) to audio transformer. Then 10= 0 ohm resistor and DUT. =20 Trace with =91scope X-Y, X is voltage across 100 ohm resistor and Y across = both contacts. =20 https://www.dropbox.com/sh/4boz6uw7rv3s8k6/r...


Core material for a low-power flyback

Started by bitrex in sci.electronics.design3 years ago 25 replies

Is powdered carbonyl iron toroid an appropriate material for winding a small flyback transformer on? Like micrometals material #7 or 8? I...

Is powdered carbonyl iron toroid an appropriate material for winding a small flyback transformer on? Like micrometals material #7 or 8? I have a number of them on hand, about half an inch outside diameter. For the inductance and ratio I need the calculator shows i'll need about 30 turns on the primary and 80 on the secondary which should easily fit using say 26 gauge wire for the primar...


copper crisis?

Started by Anonymous in sci.electronics.design2 months ago 70 replies

https://gizmodo.com/a-copper-shortage-is-likely-coming-for-the-energy-trans-1849178385 Motor and transformer design are pretty advanced. I...

https://gizmodo.com/a-copper-shortage-is-likely-coming-for-the-energy-trans-1849178385 Motor and transformer design are pretty advanced. I wonder if they could be made with more electronics and less copper somehow. Electrostatic motors miss by an enormous factor. As Africa and Asia advance and electrify, copper might be a limiting resource. Solar and wind power need a lot of copper for ...


HEI coil driver

Started by Neon John in sci.electronics.design9 years ago 9 replies

As you guys know, I'm a retired nuke. Recently I found some mailing lists for serious amateur nukes and that has caused me to "get my nuke on"...

As you guys know, I'm a retired nuke. Recently I found some mailing lists for serious amateur nukes and that has caused me to "get my nuke on" again. One thing a lot of people were complaining about was the lack of a suitable high voltage driver for the many surplus X-ray tubes that are available. Only rarely does a transformer show up and then, at least for diagnostic X-ray machine, the...


How to compute reflection coefficient from SPICE AC analysis

Started by Anonymous in sci.electronics.design5 years ago 8 replies

Could some electronics/SPICE guru please shed some light on this ? I was told that the reflection coefficient for a circuit, e.g., a L...

Could some electronics/SPICE guru please shed some light on this ? I was told that the reflection coefficient for a circuit, e.g., a L impedance transformer can be estimated from the frequency response plot of its SPICE AC analysis. If so, where could I get some details of the calculation steps. Thanks in advance.


Weird LLC current limiter

Started by Piotr Wyderski in sci.electronics.design3 years ago 3 replies

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a...

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a transformer to limit the voltage swing at the resonant capacitor. Great, but why wouldn't they use a bidirectional TVS for the same purpose? That wouldn't result in a paper, eh, would it? Best regards, Piotr


Reflow soldering for dummies

Started by mkr5000 in sci.electronics.design6 years ago 66 replies

In all my years as an electronics "hobbyist", I've never bothered to experiment with SMD and reflow soldering. I have a project now that is a...

In all my years as an electronics "hobbyist", I've never bothered to experiment with SMD and reflow soldering. I have a project now that is a very simple board and may even try some of those DIY techniques I've seen posted but also may send the board out to be populated. BUT -- inevitably I'll use a combination of SMD and some through hole, (for a pin header, transformer, terminal blocks ...


Common Mode Choke Question

Started by amdx in sci.electronics.design2 years ago 16 replies

I put a CMC on a twisted pair antenna feed line. It was between the antenna matching transformer and the feed line. It started to severely...

I put a CMC on a twisted pair antenna feed line. It was between the antenna matching transformer and the feed line. It started to severely attenuate the RF signal at about 1.7MHz. The CMC is a 25Mh. > https://tinyurl.com/y8exluwn What don't I know about CMCs? Mikek


measuring frequency

Started by Rob in sci.electronics.design5 years ago 71 replies

I would like to measure the line frequency (50 Hz) at good accuracy, like 1ppm or better, using a soundcard. I have a Linux system that is...

I would like to measure the line frequency (50 Hz) at good accuracy, like 1ppm or better, using a soundcard. I have a Linux system that is time-synchronized to GPS and consider an approach like this: - input the line frequency into a soundcard (small transformer and resistive divider to get to acceptable level) - in a software loop do: - get samples from the soundcard (highest ra...