https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 How does the mass of a transformer scale with frequency? I want to make a...

https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 How does the mass of a transformer scale with frequency? I want to make a 120v 400 Hz power supply. I might boost my 48v up to 200DC and use an isolated h-bridge out to the load, or we could put the bridge down at 48v and boost with a biggish transformer. I'll have lots of air flow, so maybe I can push things some too. ...

I am playing around with this old scope in which the power transformer winding for the CRT filaments is arcing internally. In fact years ago I did...

I am playing around with this old scope in which the power transformer winding for the CRT filaments is arcing internally. In fact years ago I did put in a hi-pot 6.3 VAC transformer and wired it to switched AC internally and it worked for a long time. But now the replacement is arcing. The filament is elevated to about 3,500 volts negative DC. What is the possibility I could find a cheapo ...

Several years ago I remember buying an Allied Electric branded power transformer similar to this...

Several years ago I remember buying an Allied Electric branded power transformer similar to this one: http://www.alliedelec.com/search/productdetail.aspx?SKU=70009000#t ab=overview But if I recall correctly the unit I bought was somewhat smaller; the primary had no center tap and the filament winding was rated for just 300 mA. It doesn't seem to be on their site anymore. Does an...

I have a little transistor radio that was drawing excessive power from the battery. It was about 125mA at 6 volts which is 10 times too much. I...

I have a little transistor radio that was drawing excessive power from the battery. It was about 125mA at 6 volts which is 10 times too much. I found I could bend the circuit board to eliminate the problem. So, I studied the thing for an hour or so and found the problem had something to do with the audio output transformer. This radio uses an input and output transformer in a push pull a...

I watched a youtube video of a guy winding his own power transformer. He used a pre-made plastic bobbin, wound the enameled wire as needed,...

I watched a youtube video of a guy winding his own power transformer. He used a pre-made plastic bobbin, wound the enameled wire as needed, and put in the steel laminations. Apparently he bought that bobbin, and the laminations to fit it. Is there a place that sells that sells the parts (bobbin and laminations)?

I am making a transformer with Epcos E55 cores of N27 ferrite. The primary will have four windings each rated for 12-15 VRMS at 50-70 kHz. I am...

I am making a transformer with Epcos E55 cores of N27 ferrite. The primary will have four windings each rated for 12-15 VRMS at 50-70 kHz. I am hoping to get up to 1500 watts, so the primary windings will need to handle up to 31 amps. The coilformer (bobbin) has 14 pins, of which 8 will be used for the primaries. The secondary will be two windings capable of 250-300 volts each at the nom...

We can sense the primary current of this transformer, with a shunt and an isolated delta-sigma ADC. The FPGA squares the samples and...

We can sense the primary current of this transformer, with a shunt and an isolated delta-sigma ADC. The FPGA squares the samples and filters, so we can pick that up and square root to get RMS current. The tranny is rated for 240 VA, which would be 9.6 amps RMS in the primary. So I ran it for a few hours with 10 amps DC in the primary. Temp rise was about 26C in free air. I think people de...

Hi all, I have always heard and used the 4 times rule for the impedance of a transformer winding. Example; To match 50 ohms to 400 ohms,...

Hi all, I have always heard and used the 4 times rule for the impedance of a transformer winding. Example; To match 50 ohms to 400 ohms, the primary inductance should be 200 ohms at the lowest frequency of interest. 4 x 50 = 200 ohms XL. Tonight I'm searching for a reference for the 4 times. I found this; http://www.scribd.com/doc/116333646/The-Four-Times-the-Impedance-Rule-for-Br...

I am learning a bit about antenna design and one of the references I found talks about coupling the antenna to the feedline with a bifilar...

I am learning a bit about antenna design and one of the references I found talks about coupling the antenna to the feedline with a bifilar wound balun transformer. I dug a bit and although I found any number of references talking about bifilar wound baluns, none explained clearly why it is important to be bifilar wound. Any pointers? Rick

Hi all, I have a 200 MHz clock signal to send across the barrier of 5 KV I'm thinking of some RF transformer - perhaps "air core" ... but...

Hi all, I have a 200 MHz clock signal to send across the barrier of 5 KV I'm thinking of some RF transformer - perhaps "air core" ... but can't find any good candidate

What do you folks think about this gem: https://www.youtube.com/watch?v=cpaWCedoptA I like the special high reluctance transformer and...

What do you folks think about this gem: https://www.youtube.com/watch?v=cpaWCedoptA I like the special high reluctance transformer and kindling used as insulation.

Can I use this for 220V input and 380V output? https://www.ebay.com/itm/255681909221 This should give me around 400V to 450V full bridge...

Can I use this for 220V input and 380V output? https://www.ebay.com/itm/255681909221 This should give me around 400V to 450V full bridge rectified DC.

This is in regard to the HV oil/water separation. The first experiment, had very good results in 5 minutes using AC. I'm going to suggest an...

This is in regard to the HV oil/water separation. The first experiment, had very good results in 5 minutes using AC. I'm going to suggest an experiment to compare AC to DC. I'm thinking running both tests at the same time from the same HV PS. I want to have two vessels setup, one driven by HV AC, and the other HV DC. If one is run from AC out of the HV transformer and then the same AC is con

This is pleasingly weird. https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0 Sort of a baseline-boosted...

This is pleasingly weird. https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0 Sort of a baseline-boosted multi-auto-transformer voltage-doubler flyback. What's strange is that adding the two snubbers increases the LT spice sim speed radically, about 10:1.

https://en.wikipedia.org/wiki/File:Royer_oscillator.gif I think the transformer phasing dots are wrong. Or, am I wrong?

https://en.wikipedia.org/wiki/File:Royer_oscillator.gif I think the transformer phasing dots are wrong. Or, am I wrong?

Could some electronics guru please help ? Maybe this is a very silly question, so please pardon me. A voltage transformer is used to provide...

Could some electronics guru please help ? Maybe this is a very silly question, so please pardon me. A voltage transformer is used to provide galvanic isolation, in a power supply, amongst other features. Is there another way to achieve galvanic isolation ? Thanks in advance.

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

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...

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

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: