new dc/dc converters

Started by John Larkin in sci.electronics.design2 months ago 40 replies

Murata makes some cool converters, with a ferrite toroid embedded in the PCB, with windings made of traces and...

Murata makes some cool converters, with a ferrite toroid embedded in the PCB, with windings made of traces and vias. https://www.dropbox.com/sh/lp9lb68pg3dohfa/AACLemXklO6JCdQRebMu1Vm6a?dl=0 Recom has some new parts, similar but they use a conventional wound transformer. https://www.dropbox.com/sh/thwbtq5mswzllg7/AACQQkqKd2XLj-MgWGonUd5Ia?dl=0 Both have standard footprints. The ...


Fun with EV to Vegas

Started by Ed Lee in sci.electronics.design3 weeks ago 14 replies

North bound at Mountain Pass is out. No problem, i'll drive pass the center media to the south bound charger. I wonder if that would damage my...

North bound at Mountain Pass is out. No problem, i'll drive pass the center media to the south bound charger. I wonder if that would damage my tires. OK, i'll bring the tire repair patch with me. https://www.plugshare.com/location/308971 Plugshare doesn't even know about the up-coming EA and Evgo stations at Primm. I wonder if they will let me tap into the high voltage transformer at the c...


PCB transmission line transformer

Started by John Larkin in sci.electronics.design8 years ago 54 replies

We've used transmission-line transformers to drive mosfet gates. We've wound them from micro-coax on ferrite toroids, with the shield being...

We've used transmission-line transformers to drive mosfet gates. We've wound them from micro-coax on ferrite toroids, with the shield being the primary and the inner conductor the secondary. Sub-ns speed and low leakage inductance. But it's labor intensive. So I was thinking about doing it on a multilayer PCB, like a 6-layer. Layers 1/3/5 could be one to three layers of spiral trace, pr...


transformer, 4 Times rule for multiple of reactance to resistance being transformed

Started by amdx in sci.electronics.design2 months ago 2 replies

I have this graph showing the 'Z_Normalized sub i' vs the multiple of reactance to resistance needing transforming. I don't know what the...

I have this graph showing the 'Z_Normalized sub i' vs the multiple of reactance to resistance needing transforming. I don't know what the 'Z_Normalized sub i' means. Or, how I could use it to calculate input resistance, current, voltage or what I can do with it. Can someone explain it to me? > https://www.dropbox.com/s/fwfzwrjxg9e7ayo/4%20Times%20Rule%20Graph.png?dl=0          


Some oscilloscope pictures

Started by Sylvia Else in sci.electronics.design1 year ago 25 replies

Shows how the power transformer is directly wired to two separate boards. Not sure how, or why, they'd want to do that. Shows the...

Shows how the power transformer is directly wired to two separate boards. Not sure how, or why, they'd want to do that. Shows the hole through which the transistor has to be soldered. Note the two resistors in plastic tubing that have one end so


800+ Watt DC-DC converter ferrite transformer design

Started by P E Schoen in sci.electronics.design9 years ago 29 replies

I want to make a DC-DC converter for 48 VDC to about 300 VDC at a = continuous=20 power of about 800W to drive a 1 to 2 HP three phase induction...

I want to make a DC-DC converter for 48 VDC to about 300 VDC at a = continuous=20 power of about 800W to drive a 1 to 2 HP three phase induction motor. I = have=20 some E55 cores and coilformers which should do the job, and also some=20 E47/20/15 which might work OK. The E55 is an Epcos type N27 and the E47 = is=20 probably the same. http://www.mouser.com/ds/2/136/e_47_20_16-75097.pdf h...


Transformer-coupled dpot

Started by Phil Hobbs in sci.electronics.design2 years ago 13 replies

This is a multi-part message in MIME format. --------------FF67D67D34458B072894D837 Content-Type: text/plain; charset=utf-8;...

This is a multi-part message in MIME format. --------------FF67D67D34458B072894D837 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit So I'm doing a spin of my swoopy nanoamp photoreceiver board, to make it smaller and more versatile. The original QL01 has two pots, one for offset and one for HF boost. The HF boost is a lead-lag network that attenu...


Tuning a Baxandall inverter.

Started by Anthony William Sloman in sci.electronics.design1 year ago 10 replies

I've just had a idea. Instead of tweaking the drive frequency to a Baxandall inverter, one could tweak the resonant frequency by switching in...

I've just had a idea. Instead of tweaking the drive frequency to a Baxandall inverter, one could tweak the resonant frequency by switching in extra capacitance with a PhotoFet. https://www.mouser.com/datasheet/2/149/h11f1m-185284.pdf Sadly. even the HF11 can only take 30V, so in Timo's inverter you'd need to add a extra 11 turn winding to his transformer and put the tuning capacito


Tariel Kapanadze - Radiant Energy from earth [2009]

Started by gabydewilde in sci.electronics.design13 years ago 3 replies

Tariel Kapanadze[1], has invented a multi kilowatt free energy generator. Several different implementations are shown[2][3][4] In one such...

Tariel Kapanadze[1], has invented a multi kilowatt free energy generator. Several different implementations are shown[2][3][4] In one such contraption the components include a radiator buried in the ground, a wire to a water pipe, a Tesla coil/joule thief, a spark gap, transformer, capacitors, 5 ferrite cores from old TV HV transformers, and some other unidentified components.[4] On July...


Homemade Wideband Current Transformer

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

Hi, Since it seems a useful thing to have, I am making a wideband current probe, ~10-1000MHz, like one of these: Every home should...

Hi, Since it seems a useful thing to have, I am making a wideband current probe, ~10-1000MHz, like one of these: Every home should have one. It's from the article: 1) They suggest an electrostatic shield made from cop


ideas on wire feedthrough sealing of oil filled HV device?

Started by Jim Horton in sci.electronics.design3 years ago 11 replies

So I decided to use mineral oil once again for my HV transformer device after debating and even trying paraffin. However, this time I want to...

So I decided to use mineral oil once again for my HV transformer device after debating and even trying paraffin. However, this time I want to be sure my wires passing through the PVC junction box are sealed correctly so no oil leaks through. The transformers will be inside a 6x6x6 PVC junction box (which takes up about 50% less volume than the prior box I used) and four connections w...


HV insulation test

Started by Winfield Hill in sci.electronics.design3 years ago 35 replies

Panasonic ELF-21C0006A common-mode choke, with insulation rating 2kV / 1min. Has two windings on plastic bobbins, on opposite ferrite-core ...

Panasonic ELF-21C0006A common-mode choke, with insulation rating 2kV / 1min. Has two windings on plastic bobbins, on opposite ferrite-core legs. Digi-Key Part Number: PLK1296-ND https://www.dropbox.com/s/wybkrot1xz6s33a/ELF-21C023A.jpg?dl=1 Candidate for 1:1 HV transformer, with 5 to 10kV pri-sec insulation, after vacuum potting, with Dow Corning Sylgard 184, rated at 12kV/mm...


Breakdown voltage

Started by Anonymous in sci.electronics.design3 years ago 21 replies

I have set up simple circuit to test breakdown voltage: transformer + voltage doubler (with 22uF filterging capacitors) delivers about 156V. ...

I have set up simple circuit to test breakdown voltage: transformer + voltage doubler (with 22uF filterging capacitors) delivers about 156V. 156V goes trough 2.2M resistor to part under test. Paralel to the part is voltmeter. This seems to give reasonable results on most parts. However on some mosfets I see curious fenomenon: reading on voltmeter slowly increase and then stabilize at high...


2 Pin VS 3 Pin Gas Discharge Tubes

Started by amdx in sci.electronics.design3 years ago 9 replies

I'm looking at Gas discharge tubes, I see 3 pin and 2 pin, but I don't find any schematic about how to connect them. My basic use is across a...

I'm looking at Gas discharge tubes, I see 3 pin and 2 pin, but I don't find any schematic about how to connect them. My basic use is across a resistor at the end of a antenna wire or across a feed line transformer. It seems obvious the two tube is applicable, but how would I use a 3 wire tube. Where does the 3rd pin go? Mikek I found 3 pin at surplus at a ver...


Removing voltage-multiplier-related flyback SMPS switching glitches

Started by Anonymous in sci.electronics.design6 years ago 13 replies

A problem encountered with medium-to-fast current-mode flyback switchers, when combining high-ratio multi-winding flyback inductors with...

A problem encountered with medium-to-fast current-mode flyback switchers, when combining high-ratio multi-winding flyback inductors with multipliers: When Q1 switches on, a large current surge flows as Cpump charges from Cmult1 via D2. At Q1, the surge magnitude is multiplied by the transformer ratio. On simulation, U1 senses this via Rs and cuts Q1 off instantly, crippling the switcher -- ...


Super low power isolated MOSFET driver

Started by Piotr Wyderski in sci.electronics.design3 years ago 25 replies

Hi, I need to slowly drive a high-voltage high-side MOSFET in a 5kV isolated setup. This use case reminds an electronic fuse: the MOSFET is...

Hi, I need to slowly drive a high-voltage high-side MOSFET in a 5kV isolated setup. This use case reminds an electronic fuse: the MOSFET is expected to be almost always ON, but the driver needs to start in an OFF condition. Generally the answer would be Si8261, but it requires ~50mW. So I have devised a much less energy hungry driver based on a tiny 1:1 bipolar drive pulse transformer ...


Any tricks to winding high ratio, high impedance RF transformers

Started by amdx in sci.electronics.design2 years ago 41 replies

I just wound what I thought would be a 350? to 23k? AM BCB transformer. I put a 23k?n the secondary and the primary measures R=14? and X=...

I just wound what I thought would be a 350? to 23k? AM BCB transformer. I put a 23k?n the secondary and the primary measures R=14? and X= -43? at 1MHz. I used a #73 Binocular core. Looking for about 8, 9, or 10 to 1 turns ratio. The inductances measure correct and the step up voltage measures correct. I'm guessing the problem is winding capacitance. But, I'm not sure. Any tricks to


25kV AC

Started by Winfield Hill in sci.electronics.design3 years ago 72 replies

We need a 25kV rms AC signal. OK, that's 70kV p-p. I had a 30kV Trek model 678 amplifier, a huge beast procured on eBay, but I fear it...

We need a 25kV rms AC signal. OK, that's 70kV p-p. I had a 30kV Trek model 678 amplifier, a huge beast procured on eBay, but I fear it was thrown away in a downsizing move, damn! With that we could make a 10kV rms AC signal, at a frequency of our choice. And maybe transform it up to 25kV. Years ago I made RIS-333 / RIS-470, a 10kV 600kHz amplifier / resonant-transformer for ...


Ethernet RJ45 jack - what do the transformer centre taps do?

Started by Peter in sci.electronics.design3 years ago 6 replies

This is a common type of jack with integrated magnetics http://www.kosmodrom.com.ua/pdf/HR911105A.pdf It connects the txf centre taps via...

This is a common type of jack with integrated magnetics http://www.kosmodrom.com.ua/pdf/HR911105A.pdf It connects the txf centre taps via 75R resistors to a 1000pf cap which then (pin 8) goes to the circuit ground. What does this do? There are versions of the 10/100 jack which don't use the centre taps at all e.g. http://peter-ftp.co.uk/screenshots/20191119201261014.jpg


Symmetric DC-DC power transformer

Started by Anonymous in sci.electronics.design2 years ago 2 replies

I am working on a dual active bridges (4 mosfets instead of 4 diodes) by switching directions using either: 555, CPLD, FPGA or micro, depending...

I am working on a dual active bridges (4 mosfets instead of 4 diodes) by switching directions using either: 555, CPLD, FPGA or micro, depending on timing complexity. In the simplest case, just a 555 switching primary and secondary at the same time. In more complicated case, a micro switching with turn-on delay T1, turn-on time T2, turn-off delay T3 and frequency F1. What are the