Small xformer with less than 6mm build height

Started by Klaus Kragelund in sci.electronics.design11 years ago 6 replies

Hi I am looking for a small transformer (preferable SMD), than has a build height of less than 6mm and an isolation voltage of 2.5kV. I am...

Hi I am looking for a small transformer (preferable SMD), than has a build height of less than 6mm and an isolation voltage of 2.5kV. I am designing a 20V/3.3V 150mW forward converter and have very little space available. I found these: http://www.murata-ps.com/data/magnetics/kmp_782485c.pdf (is less than 60cents) But its a little to the tall side Any other candidates? Tha...


HV creepage requirements on internal layers of PCB

Started by sea moss in sci.electronics.design4 years ago 22 replies

For my day job I'm attempting to design a planar transformer for an LLC converter, which pushes up to 50W. The tricky part is that some of the...

For my day job I'm attempting to design a planar transformer for an LLC converter, which pushes up to 50W. The tricky part is that some of the secondary windings require 3.5kV of isolation between them. This will go on a board which will be potted, and we use 100V/mil clearance and 20V/mil creepage as our design rules for everything once it's been potted. However, I'm trying to figure out w...


Skybuck's Review of Transformers Fall of Cybertron (And story stuff for a potential sequel)

Started by Skybuck Flying in sci.electronics.design10 years ago 2 replies

Hello, The first thing I want to write about this video game is that it is a dream come true. When I was a little kid dreaming/fantasizing...

Hello, The first thing I want to write about this video game is that it is a dream come true. When I was a little kid dreaming/fantasizing about being in the transformers universe/on cybertron I could only dream of a game like this, the game is visually much better than my dreams could ever be ! So almost needless to say, for a real transformer fan this game is to die for and a mu...


Cute little circuit

Started by Tim Williams in sci.electronics.design10 years ago 20 replies

http://webpages.charter.net/dawill/Images/High_Voltage_Generator.png (That feedback winding is part of the main transformer...) Great...

http://webpages.charter.net/dawill/Images/High_Voltage_Generator.png (That feedback winding is part of the main transformer...) Great regulation, as TL431 always provides. Efficiency probably around 50% at full output, not great but reasonable given the control method. PSRR isn't all that great, simply because the feedback network is VCC-referenced. Output ripple is in the mV. Hmm, ...


Why not turn off power grid one hour before hurricane sandy ?

Started by Skybuck Flying in sci.electronics.design10 years ago 58 replies

Hello, I was wondering to myself before Sandy hit if the power grid in New York should be turned off, to prevent casualties/deaths and...

Hello, I was wondering to myself before Sandy hit if the power grid in New York should be turned off, to prevent casualties/deaths and ofcourse damage. (Wow this message got interrupted by a red heli flying above my appartment complex twice, it was quite close, fortunately I am still alive lol.) This could have prevented the power transformer from blowing up. Bye, Skybuck.


Minimizing destructive HV spikes on square wave push-pull MOSFET drive to transformer

Started by P E Schoen in sci.electronics.design10 years ago 30 replies

I had posted about success with fast MOSFET gate drivers on my 1500 VA = DC-DC=20 converter. The UCC27321 drivers provide up to 9 amps so the...

I had posted about success with fast MOSFET gate drivers on my 1500 VA = DC-DC=20 converter. The UCC27321 drivers provide up to 9 amps so the MOSFETs now=20 switch on and off very quickly compared to the previous drivers, which = were=20 actually gates of an LM324 op-amp. So, although I got better efficiency = and=20 I was able to apply 25 VDC, the 30 volt TVS diodes from each drain to = t...


Preventing a BJT from exploding using only base current

Started by Aleksandar Kuktin in sci.electronics.design7 years ago 16 replies

Hi all! TL;DR: when a BJT sits naked (no DC resistances on either the emitter or collector, but well controlled base current) between Vcc and...

Hi all! TL;DR: when a BJT sits naked (no DC resistances on either the emitter or collector, but well controlled base current) between Vcc and GND, is it safe to use ONLY the base current to prevent it from releasing magic smoke? Details below. I'm building a transmitter for a wired interface (Ethernet). I chose to drive the transmission line itself with a transformer which is in turn...


Tape wound toroid for 40kHz

Started by Clive Arthur in sci.electronics.design5 years ago 29 replies

Happy Victory at Adwa Day. I need to make or have made a toroidal transformer with multiple turns to fit over a ~5" ~125mm conducting tube...

Happy Victory at Adwa Day. I need to make or have made a toroidal transformer with multiple turns to fit over a ~5" ~125mm conducting tube acting as a single turn through the middle. A ferrite core would be good, but finding the exact size would be difficult. Tape wound Silicon Iron as used on mains toroids sounds like the easiest way to fabricate one, but is there any chance of it ...


DC/DC converter - 8KW

Started by test in sci.electronics.design11 years ago 29 replies

Hi. I need some simple low cost schematics how to make 8KW converter that can convert from 72 to 460V . The basic idea is to wind some strong...

Hi. I need some simple low cost schematics how to make 8KW converter that can convert from 72 to 460V . The basic idea is to wind some strong transformer and to rise the frequency to 200 - 300 HZ + IGBT. There is no need for riple and stable voltage or for PWM control because the inverter is connected to DC link of micromaster and mm is connected to AC 8kw motor. The motor should not p...


Random thoughts on hot wires

Started by Tim Wescott in sci.electronics.design11 years ago 26 replies

So, the approved method of cutting styrofoam for model airplane wings is to get a nichrome wire (or stainless -- you pay extra if it's called...

So, the approved method of cutting styrofoam for model airplane wings is to get a nichrome wire (or stainless -- you pay extra if it's called "heater wire") hot, and run it through the styrofoam. Many folks do this using a lamp dimmer connected straight (no isolation transformer!) to the wire that they're playing with just inches from their hands. For some _really odd_ reason I don't w...


PD Impulse detection 1 picosecond , a better mousetrap possible?

Started by Anthony Stewart in sci.electronics.design9 years ago 1 reply

I want to build a better Partial Discharge (PD) detector for events that of= ten Oil filled Transformers. THese events are the same as ESD finger...

I want to build a better Partial Discharge (PD) detector for events that of= ten Oil filled Transformers. THese events are the same as ESD finger discha= rges but internal to the transformer. I have measured about 2 Watt peak pul= ses with < 1ns rise time and < 10ns pulse duration. Typically these are det= ected with capacitive or inductive conducted current sensors or radiated in= ductive se


Antiseptic Convertor

Started by Vladimir Vassilevsky in sci.electronics.design9 years ago 20 replies

I had to make +100...+400V from +9V at power level up to 10W. The obvious solution was flyback convertor; using wal-wart power supply...

I had to make +100...+400V from +9V at power level up to 10W. The obvious solution was flyback convertor; using wal-wart power supply transformer in backwards mode. However the particularly septic thing about it was huge stray inductance both on primary and secondary side. So, after scorching some parts, I came up with following antiseptic solution: http://www.abvolt.com/misc/antise...


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...


Q of LC circuit

Started by Jessica Shaw in sci.electronics.design11 years ago 84 replies

Hi, The load schematic is at the following link http://img28.imageshack.us/img28/6703/loadf.jpg I am driving it using the H brdige...

Hi, The load schematic is at the following link http://img28.imageshack.us/img28/6703/loadf.jpg I am driving it using the H brdige circuit . What is the best way to calculate the Q of this Load. I read the following article about measuring Q of this circuit http://www.crystal-radio.eu/enqmeting.htm The article says that inorder to measure the Q, I need a transformer and a fun...


Lighting a LED with a lighter

Started by Jan Panteltje in sci.electronics.design10 years ago 6 replies

Got a light? http://youtu.be/hjsgwQs0LTw I added a power MOSFET, it drives the output via an extra turn on the transformer, At 15 mV the LED...

Got a light? http://youtu.be/hjsgwQs0LTw I added a power MOSFET, it drives the output via an extra turn on the transformer, At 15 mV the LED comes on. more light, the resistance of the thermocouple wire I use now really limits power (= LED current) The sky is the limit I think. New circuit diagram, update part in red: http://panteltje.com/pub/lighting_a_LED_with_a_candle_circuit_dia...


Mounting Straps?

Started by Jim Thompson in sci.electronics.design5 years ago 13 replies

Do standard mounting straps exist for mounting this... I want to mount it under a cabinet. ...

Do standard mounting straps exist for mounting this... I want to mount it under a cabinet. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Sy


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


Highish Current/Lowish Voltage Rectification

Started by Cursitor Doom in sci.electronics.design8 years ago 37 replies

Hi all, I have a welding transformer that produces an output of either 50V AC or 80V AC (open circuit voltage) at a range of currents of up to...

Hi all, I have a welding transformer that produces an output of either 50V AC or 80V AC (open circuit voltage) at a range of currents of up to 200 Amps. I want to convert this to DC, preferably by full wave rectification, whilst maintaining the same range of currents. This will then form the power supply for a dual purpose TIG welder/plasma cutter I'm going to build. Any suggestions as t...


Stumped by odd LM7815 output -- request help

Started by Anonymous in sci.electronics.design7 years ago 56 replies

Could some electronics guru please help ? I am building a +/- 15 Volt 2 A (max) power supply for personal use, and I am very puzzled by the...

Could some electronics guru please help ? I am building a +/- 15 Volt 2 A (max) power supply for personal use, and I am very puzzled by the behavior of the LM 7815 voltage regulator. THe step down transformer is a 230 Volt AC input 30 - 0 30 Volt 2 A (max) output. I use a standard bridge rectifier consisting of four 1N4007 rectifier diodes. The DC voltages at the end of the rectifier ar...