1:1 Coupling Transformer 20Hz to 10KHz

Started by Robert Stevens in sci.electronics.design6 years ago 26 replies

I am looking for a transformer to couple a 10W audio signal to a resistive load. It needs to have a "flatish" frequency response from 20Hz...

I am looking for a transformer to couple a 10W audio signal to a resistive load. It needs to have a "flatish" frequency response from 20Hz to 10KHz, or else vary no more than about 25% over the above range. Turns ratio should be relatively low, preferably 1:1. Input impedance is the usual 4-8 Ohms. I have tried a variety of off-the-shelf mains and PA transformers. They either have t...


Uart through an audio transformer

Started by Martin Griffith in sci.electronics.design13 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.design4 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 ...


Off-the-Shelf 70KHz Step-Up Transformer

Started by Kevin Foster in sci.electronics.design6 years ago 13 replies

I am looking for an off-the-shelf transformer that will step up a 12Vpp 70KHz square wave to around 10-20KVAC. It is for an electrostatic...

I am looking for an off-the-shelf transformer that will step up a 12Vpp 70KHz square wave to around 10-20KVAC. It is for an electrostatic experiment, so very little output current is needed. I have tried ignition transformers, auto coils, audio coupling, and TV flybacks, but none were efficient at that high frequency. I can not afford to have one custom wound. Does anyone have any...


trigger transformer

Started by John Larkin in sci.electronics.design7 years ago 21 replies

I was thinking about triggering a TinyLogic one-shot that will be 4 KV off ground. How about a surface-mount inductor on one side of a PCB,...

I was thinking about triggering a TinyLogic one-shot that will be 4 KV off ground. How about a surface-mount inductor on one side of a PCB, and another on the opposite side, as a transformer? Whack the primary with a big fast pulse, and it might make enough on the other side to fire a 1G123. Gotta try it, I guess. (Remember to cut away the ground plane, dummy!) Any other ideas? I want...


Permanent Ring Magnet as Transfomer Core

Started by Ken Sutton in sci.electronics.design10 years ago 13 replies

Can anyone tell me what the result would be of using a permanent ring magnet as a core for a toroidal transformer? For example, how would it...

Can anyone tell me what the result would be of using a permanent ring magnet as a core for a toroidal transformer? For example, how would it change the dynamics of the field between the pri and sec if used in a step-up transformer? I seem to recall a patent based on this configuration. Ken Sutton.


LT Spice library IRFZ44, Centered tapped Transformer and PV cell

Started by Qasim khan in sci.electronics.design2 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


Chosing class A output transformer

Started by Archival in sci.electronics.design10 years ago 22 replies

How does one chose a good class A output transformer? I'm looking to build = a simple class A low power < 15W that can drive 4, 8, or 16 ohms...

How does one chose a good class A output transformer? I'm looking to build = a simple class A low power < 15W that can drive 4, 8, or 16 ohms and has hi= gh linearity with a separate negative feedback coil(so switching load sizes= does change the feedback path). Any recommendations?


why snubber capacitors on output diodes?

Started by Yzordderrex in sci.electronics.design7 years ago 4 replies

I did a full bridge phase shift ZVS converter many years ago. I remember u= sing some fairly significant RC snubbers on the 2 output...

I did a full bridge phase shift ZVS converter many years ago. I remember u= sing some fairly significant RC snubbers on the 2 output rectifiers. I can't seem to recall the exact explanation for why they are needed. I'm = guessing the leakage reactance in the transformer has something to do with = it. I draw the converter with a pair of inductors on the transformer outpu= t to represent t...


Transformer/excitation coil for Armstrong oscillator

Started by Anonymous in sci.electronics.design3 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...


Transformer Wanted

Started by Anonymous in sci.electronics.design3 years ago 20 replies

I looked, didn't find much. Audio, high quality like a good ass old tube amp, they had them 5 - 100,000 Hz with less than a percent THD. That...

I looked, didn't find much. Audio, high quality like a good ass old tube amp, they had them 5 - 100,000 Hz with less than a percent THD. That level of quality, however the specs are different. I don't need a primary. "Primarily" what I need is a center tapped choke, but if I can just get a 1:1 audio transformer it would work given one thing - the primary and secondary must be identical. ...


Vaccum capacitor failure oddness.

Started by Maynard A. Philbrook Jr. in sci.electronics.design8 years ago 4 replies

While analyzing a problem with a small (150Kwatt oscillator) circuit, we discovered a faulty 200 pf 30VK vacuum cap. This was found via...

While analyzing a problem with a small (150Kwatt oscillator) circuit, we discovered a faulty 200 pf 30VK vacuum cap. This was found via a series of HI-POT testing, starting with the filament transformer (250 amps) which acts as the tube heater and tap for the cathode (-) voltage ( the + is grounded in this circuit) First intentions were to determine if the transformer had a leak...


capacitor gets hot in a HF-HV resonant circuit

Started by blisca in sci.electronics.design6 years ago 28 replies

Hi i was asked to help some friends in a task that is unusual for me: I have to generate a 100 Vpp -150 KHz ringing on a single turn of a...

Hi i was asked to help some friends in a task that is unusual for me: I have to generate a 100 Vpp -150 KHz ringing on a single turn of a transformer secondary. I generate an adjustable PWM with a microcontroller,then a driver drives a N MOSFET connected to VDD via a couple of turns(the primary of the transformer),paralleled by a capacitor** With a pulse width of about 7us i have ...


Sinewave inverter

Started by Sylvia Else in sci.electronics.design7 years ago 7 replies

I had (naively, perhaps) thought that the main reason for having a transformer in a sinewave inverter circuit was to provide isolation,...

I had (naively, perhaps) thought that the main reason for having a transformer in a sinewave inverter circuit was to provide isolation, between the mains voltage output and the low voltage input, so that the latter would not be live. My thinking was then that if that's not a consideration (because the input is also at a dangerous voltage) then one could dispense with the transformer. ...


Transformer design question -- what does 'strand' mean

Started by Anonymous in sci.electronics.design6 years ago 12 replies

Could some electronics guru please clarify this a bit ? Going over Col. Lyman's classic text on inductor/transformer design (especially...

Could some electronics guru please clarify this a bit ? Going over Col. Lyman's classic text on inductor/transformer design (especially switching transformers) I came upon the term 'strands'. For example, the total number of turns is 40, and the number of strands is 2. What wxactly does this mean ? I am afraid my concepts are a bit rusty at present, as I have been out of touch with this...


Ebay funny

Started by Michael A. Terrell in sci.electronics.design9 years ago 17 replies

Read the label on the transformer and count the errors. :) If that link doesn't work, here is the...

Read the label on the transformer and count the errors. :) If that link doesn't work, here is the item http://www.ebay.com/itm/300806901369 Also: The photo says 220V, the listing says 110V.


Cheap AndEasy 6.3 Volts

Started by Anonymous in sci.electronics.design4 years ago 64 replies

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 ...


Transformer secondary winding question

Started by Anonymous in sci.electronics.design8 years ago 2 replies

Could some electronics guru please shed some light on this. I am helping a colleague of mine wind a step down transformer, as a weekend...

Could some electronics guru please shed some light on this. I am helping a colleague of mine wind a step down transformer, as a weekend project. We have done all the calculations, The secondary is center tapped, and my understanding is that a "pig-tail" has to be created, which serves as the center tap. The secondary coil is made of two coils, such that the end terminal of one coil is ...


Standard isolation transformer lamination dimensions

Started by Anonymous in sci.electronics.design6 years ago 2 replies

Could some electronics guru please help ? I am looking for an URl or online documentation that lists the dimensions of commonly available...

Could some electronics guru please help ? I am looking for an URl or online documentation that lists the dimensions of commonly available isolation transformer lamination dimensions. I have visited the Web sites of some companies that list details of only their own products (obviously) but it is not clear if what they stste are standard vslues or custom. Thanks in advance.