Grounded Bridge

Started by Anonymous in sci.electronics.design8 years ago 4 replies

A Crown MT series, I think 1200 came across my bench. It has a patented "grounded bridge output circuit. I have been thinking about the...

A Crown MT series, I think 1200 came across my bench. It has a patented "grounded bridge output circuit. I have been thinking about the ramifications of this design. The disadvantages : Of course you need a separate power transformer for each channel because half of the audio voltage is imposed on the secondary of the power transformer. Thios must cause some problems with c


Inductive digital isolator

Started by Andrzej Ekiert in sci.electronics.design10 years ago 31 replies

Hi all, The reason for this post is that I want to safeguard my idea from any patenting attempts. Releasing the details to the public domain...

Hi all, The reason for this post is that I want to safeguard my idea from any patenting attempts. Releasing the details to the public domain should do the trick, so here they are: Imagine a transformer built from two coils routed on a PCB on two different layers (top and bottom for example). The thickness of the PCB provides the isolation required. Transmission is performed by shor...


Amorphous metal tape

Started by Clive Arthur in sci.electronics.design1 year ago 11 replies

I need to make an inductor - a couple of mH at a couple of amps. It has to fit in an awkward space, roughly oval toroidal and nothing off the...

I need to make an inductor - a couple of mH at a couple of amps. It has to fit in an awkward space, roughly oval toroidal and nothing off the shelf. Nothing I can do about the space. So this tape - I know nothing of it except that it can be used for transformer cores. Can I buy a roll and wind my own core on a former? Anyone used it? -- Cheers Clive


Lead-acid charger/starter

Started by Don Y in sci.electronics.design3 weeks ago 12 replies

The "charge" functions are pretty easily understood. But, is the "engine start" function just a whopping big transformer-rectifier-filter...

The "charge" functions are pretty easily understood. But, is the "engine start" function just a whopping big transformer-rectifier-filter sitting behind the clamps? I'm speaking of the ~200A load current devices, not the smaller 50A; something along the lines of:


isolated DC/DC converter

Started by John Larkin in sci.electronics.design11 years ago 189 replies

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil...

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil inductor as the transformer. The complementary emitter followers will have no shoot-through and can have controllably slow switching edges, since they will just follow the base drive. Anybody got ideas for the base driver device? Ideally it would be s...


300V power supply.

Started by George Herold in sci.electronics.design5 years ago 40 replies

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter...

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter solution. I started here, (of course) http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf Figure 13 looked nice. I then priced a pico 32195 transformer. ~$100! Ouch! (maybe I can find a cheaper one.) I then was tr...


PSU capacitor choice

Started by Cursitor Doom in sci.electronics.design3 years ago 15 replies

Greetings, gentlemen, I'm attaching a scan of the rectifier board from an HP8547A network analyser. I'm just wondering how the designer(s)...

Greetings, gentlemen, I'm attaching a scan of the rectifier board from an HP8547A network analyser. I'm just wondering how the designer(s) arrived at the choice of value for the caps across the incoming supply from the mains transformer secondary windings (the caps immediately before the bridge rectifiers)? In case you can't make it out, the values are 0.047uF, 0.22uF, 0.47uF and 0.04...


Transformer bobbins/coil formers

Started by Clive Arthur in sci.electronics.design3 years ago 14 replies

For an RM ferrite core (RM8 in my case) you can buy two types of bobbin, a single section and two sections, though the latter is less often...

For an RM ferrite core (RM8 in my case) you can buy two types of bobbin, a single section and two sections, though the latter is less often stocked. Assuming there are two windings and that the wire will fit on either type, it seems to me that the two section bobbin would have less inherent inter-winding capacitance and better isolation, though you can't easily wrap a copper tape screen...


Guesstimate A Transformer

Started by Anonymous in sci.electronics.design4 years ago 14 replies

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a...

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a certain feature I need for this. This is a mobile audio amplifier. The basic configuration is shown at the end of this post in Spice. The coils, L1 and L2 are actually a center tapped winding. What I want to know is how much power dare


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,...


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.design4 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 ...


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


Common Mode Choke Question

Started by amdx in sci.electronics.design3 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


Spot the Design Error 2

Started by Phil Allison in sci.electronics.design3 years ago 34 replies

Hi to my many admirers, see schem for tube instrument amplifier, the famous Fender "Bassman 50"....

Hi to my many admirers, see schem for tube instrument amplifier, the famous Fender "Bassman 50". https://schematicheaven.net/fenderamps/fender_bassman50.pdf Thousands made and sold, yet it has a fatal design flaw. Owners can, in a single step that they would never imagine was hazardous, instantly damage or destroy output tubes and/or the output transformer. This during ...


Why does it work so well?

Started by Piotr Wyderski in sci.electronics.design6 years ago 8 replies

I have the following simple converter: CD4093 drives the power logic shift register's NPIC6C596A OE pin with 500kHz square wave signal...

I have the following simple converter: CD4093 drives the power logic shift register's NPIC6C596A OE pin with 500kHz square wave signal with duty cycle 40%. Both chips are powered from 5V, the shift register is set to all ones. Hence I have 8 modulated open drain channels, everything works as expected. Now I connect a 1:1 transformer wound on a PC40 6mm toroid (AL=2300), 16 turns each. The p...


LT spice, leakage inductance

Started by John Larkin in sci.electronics.design5 years ago 227 replies

I'm simulating a flyback switcher and noticed that any K < 1 in the transformer radically slows down the sim, which is annoyingly...

I'm simulating a flyback switcher and noticed that any K < 1 in the transformer radically slows down the sim, which is annoyingly slow already... 90 seconds to sim 60 ms of startup and a little pulsed load blip. Maybe 6:1 slower with a little leakage inductance. So I only include leakage inductance to tweak the snubber. -- John Larkin Highland Technology, Inc picosecond


Old-timey design from not too long ago

Started by bitrex in sci.electronics.design6 years ago 17 replies

The Yamaha TX81Z, circa 1986: http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg Big transformer, linear regulators, two-sided...

The Yamaha TX81Z, circa 1986: http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg Big transformer, linear regulators, two-sided board, bunch of DIPs. Looks like the power switch is on the left at the back, and they've routed some long piece of metal around the regulator heatsinks all the way to the front panel. Anyone know why they'd do that? The ICs seem scattered all ov...