Transformer Question

Started by Anonymous in sci.electronics.design6 years ago 91 replies

I was looking at the commercial isolation transformers and they are very costly, so I decided to build my own. After all, all they are is...

I was looking at the commercial isolation transformers and they are very costly, so I decided to build my own. After all, all they are is a transformer with a power cord on the primary and an outlet (and fuse) on the secondary. And I already have an enclosure to put it in. I'm looking at a bare transformer to use as an 120v isolation Transformer. (120v in, 120v out). The transformer primar...


What is the Q factor formula of a transformer

Started by amal banerjee in sci.electronics.design11 months ago 3 replies

Could some electronics guru here shed some light on this ? What is the formula for a transformer, consisting of two magnetically coupled...

Could some electronics guru here shed some light on this ? What is the formula for a transformer, consisting of two magnetically coupled inductors ? For a standalone inductor it is Q = wL/R. What are L, and R in the case of a transformer. Specifically, how does one take into account the mutual inductance, and what is the value of R ? All hints, suggestions will be greatly appreciated. Thanks ...


RF transformer

Started by Robert Baer in sci.electronics.design9 years ago 40 replies

I understand, that with the proper winding configuration, that a 90 degree phase shift can be achieved between primary and resonant...

I understand, that with the proper winding configuration, that a 90 degree phase shift can be achieved between primary and resonant secondary. That is done with a tapped secondary on a FM discriminator transformer. What are the guidelines and requirements needed to construct such a transformer at a given frequency OTHER than the standard 10.7Mhz? Say, on a form in the one inch d...


Cooling of overloaded transformer

Started by Klaus Kragelund in sci.electronics.design4 years ago 97 replies

Hi When I go to the states, I usually buy white goods, half price than in Europe So I have a 600W 230V to 115V transformer installed in a...

Hi When I go to the states, I usually buy white goods, half price than in Europe So I have a 600W 230V to 115V transformer installed in a cabinet Now I have bought a 1300W toaster Instead of buying a new transformer, I am seriously considering just overloading it, but then keeping the heat down by forced convection, namely a fan Anyone tried overloading transformers before? Rega...


Current transformer

Started by Tim Williams in sci.electronics.design11 years ago 114 replies

Would've been nice if I had known a current transformer isn't a very good transformer. Instead of two terminals, it acts more like a single...

Would've been nice if I had known a current transformer isn't a very good transformer. Instead of two terminals, it acts more like a single terminal, with your poor burden resistor caught in the middle. Ah well, such is basic research... Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms


Toroidal Transformer Screening

Started by Syd Rumpo in sci.electronics.design7 years ago 11 replies

Hi Another magnetics question! I have a SMPS which uses a toroidal ferrite transformer. It switches at ~100kHz, works very well, it's not...

Hi Another magnetics question! I have a SMPS which uses a toroidal ferrite transformer. It switches at ~100kHz, works very well, it's not my design and I can't change it. However, it introduces noise at about 50kHz onto/into my electronics which causes a problem. After much experimentation, I found that putting an earthed screen around the transformer kills the problem quite dra...


high-voltage transformer

Started by Winfield Hill in sci.electronics.design3 years ago 12 replies

My 1:1 high-voltage transformer is coming along well. This is to make 5V, 12V, or whatever at high voltages. I'll be using it at 6kV, but...

My 1:1 high-voltage transformer is coming along well. This is to make 5V, 12V, or whatever at high voltages. I'll be using it at 6kV, but it's passing tests at 9kV, and I'll do a weekend at 11kV before pronouncing it OK. The transformer is a small 50-cent common-mode choke, TAIYO YUDEN p/n TLF9UA102W0R8K1, footprint only 11x17mm. The pins are spaced 8mm. We potted it with vacuum ai...


50 ohms to 0.02 ohm transformer

Started by amdx in sci.electronics.design6 years ago 37 replies

I want to build a 50 ohm to 0.02 ohm transformer. It needs a 50 to 1 turns ratio. It takes a low A sub L core to make such a thing. I have a...

I want to build a 50 ohm to 0.02 ohm transformer. It needs a 50 to 1 turns ratio. It takes a low A sub L core to make such a thing. I have a toroid with an A sub L of 75. That only needs 29 turns for my frequency of interest 500KHz to 1700kHz. I also have some potcores that I could gap to lower the A sub L. What would make a better transformer a toroid or a gapped potcore? I plan 50...


Small transformers and LTSpice simulation

Started by Grant in sci.electronics.design11 years ago 30 replies

I have a design that could use three or four winding toroid transformer. In the LTSpice notes they suggest keeping the transformer coupling...

I have a design that could use three or four winding toroid transformer. In the LTSpice notes they suggest keeping the transformer coupling at 1.0 or -1.0 otherwise there's lots of high frequency noise generated, I'm not sure if that's real world, or the simulation going silly? What I'm wondering is just how much coupling should I expect to see in a real world transformer of around f...


Bandaxall Oscillator

Started by Kooner in sci.electronics.design10 years ago 15 replies

Hello, I made a Bandaxall Class D Oscillator with a 11mm x 7mm pot core transformer and it works quite well. The input is 8VDC and...

Hello, I made a Bandaxall Class D Oscillator with a 11mm x 7mm pot core transformer and it works quite well. The input is 8VDC and the secondary output is 800V peak to peak. The transformer is very difficult (for me) to wind because the secondary uses #46 awg wire and it breaks easily. Also, I would like to use a shorter transformer, around 5mm tall. There are smaller pot cores but ther...


transformer K in LT Spice

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

I recall seeing, somewhere, that LT Spice may handle a transformer with K=1 different from one where K

I recall seeing, somewhere, that LT Spice may handle a transformer with K=1 different from one where K


IIR constant phase shift network, absolute vs. relative phase

Started by bitrex in sci.electronics.design3 years ago 14 replies

In the Hilbert transformer-based phase shifting network implementation a la: They measure the shift of the final y output as a relative...

In the Hilbert transformer-based phase shifting network implementation a la: They measure the shift of the final y output as a relative phase with respect to the I output of the digital Hilbert transformer. It looks like it's possible to also make an absolute phase shift with respect to the input signal to the transformer by adjusting


Design Me A Transformer, I Will Pay

Started by Anonymous in sci.electronics.design3 years ago 111 replies

I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay...

I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay someone. I need an audio transformer, actually a center tapped choke. I can't seem to source it so custom mad, oh well. You get what you pay for. This has to be high quality for audio, not saturate or any of that and I need a low DCR.


gEDA PCB footprints for potted transformers.

Started by Johann Klammer in sci.electronics.design3 years ago 1 reply

I looked at that gedafootprints site but they only had one(1) transformer of the wrong size. So here's my .inc file for those. Beware....

I looked at that gedafootprints site but they only had one(1) transformer of the wrong size. So here's my .inc file for those. Beware. dimensions were hand transcribed from a pdf. # single output safety transformer \n $1: canonical name # $2: nameonpcb # $3: value # $4: A (mechanical dimensions in um) # $5: B # $6: C # $7: D # $8: E # $9: F # $10: pin size define(`PKG_BLOCK1


oscillator for driving a transformer

Started by panfilero in sci.electronics.design10 years ago 12 replies

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable...

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable multivibrator with a = couple of caps and transistors but i couldn't get it to drive the transform= er, it wouldn't even make anything close to a nice square wave.... anyone k= now of a better simple oscillator circuit I could use to do this? thanks! ...


Uart through an audio transformer

Started by Martin Griffith in sci.electronics.design14 years ago 27 replies

Any rules of thumb about sending a 9600 baud UARTsignal ,from an 8051 through a telecom type V90 audio transformer, (LT spice K L1 L2 1 @ 4mH Rs...

Any rules of thumb about sending a 9600 baud UARTsignal ,from an 8051 through a telecom type V90 audio transformer, (LT spice K L1 L2 1 @ 4mH Rs = 10R) I only need about 8 bytes of data, and LTspice seems to need a square wave for about a millisecond before it settles down. So a long sync word of 010101 etc then a start byte? I'll pad the sig down to 100mV or so martin


class D amp

Started by John Larkin in sci.electronics.design5 years ago 82 replies

I want to build an AC source to test synchros/resolvers/RVDTs. The target is 400 Hz 30 VRMS at maybe 30 VA, but we might want to...

I want to build an AC source to test synchros/resolvers/RVDTs. The target is 400 Hz 30 VRMS at maybe 30 VA, but we might want to simulate aircraft "wild power" and drive LVDTs, so maybe 250 Hz to a few KHz. I'm thinking of using half of a TPA3251 audio amp and a step-up transformer. Like this maybe: https://www.dropbox.com/s/eikiu79jv4cjxqp/P548_WB_1.JPG?raw=1 The transformer DCR is ...


LT Spice library IRFZ44, Centered tapped Transformer and PV cell

Started by Qasim khan in sci.electronics.design3 years ago 13 replies

Hi Dear all, Please help me to add following libraries in LT-Spice. 1. RFZ44 2. Centered tapped Transformer 3. PV cell Thank...

Hi Dear all, Please help me to add following libraries in LT-Spice. 1. RFZ44 2. Centered tapped Transformer 3. PV cell Thank you in advance for your answer and cooperation. Regards, Qasim


Transformer/excitation coil for Armstrong oscillator

Started by Anonymous in sci.electronics.design4 years ago 11 replies

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to...

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to be with designing the transformer and/or excitation coil. Are there any good tutorials or related material online. Any hints/ suggestions would be of immense help. Thanks in advance.


Help With Royer Oscillator

Started by Kooner in sci.electronics.design11 years ago 19 replies

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by...

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by the transformer inductance and winding capacitance. The schematic looks like a multivibrator except the reistors in the collectors are replaced withthe half primaries of the pushpull transformer. This circuit has BJTs and has a sine wave output but I w...