How to filter transformer output

Started by Daku in sci.electronics.design10 years ago 7 replies

Could some electronics guru please help ? I have a SPICE simulation of a simple inverter(DC-> AC). The output of the transformer is a...

Could some electronics guru please help ? I have a SPICE simulation of a simple inverter(DC-> AC). The output of the transformer is a square wave within some rails. If I pass it through a smoothing filter (e.g., RC with cutoff at 60.0Hz), the output is in the mV. In this case, what is the best way to remove higher harmonics from the square wave output ?


Allied tube power transformer

Started by bitrex in sci.electronics.design7 years ago 3 replies

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...


Audio transformer as step up transformer

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

I have a few little PCB mount audio impedance matching transformers, the impedance transformation given on the bag is 500 to 4...

I have a few little PCB mount audio impedance matching transformers, the impedance transformation given on the bag is 500 to 4 ohms. Would these work OK in reverse to step low voltage up to high voltage at a few mA output current and maybe 30 kHz? Efficiency not terribly important... -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/


Flux cancellation

Started by Piotr Wyderski in sci.electronics.design3 years ago 3 replies

In this short movie the guy explains the technology behind his 1kW LLC converter: https://youtu.be/wtcn6rZE1Eg At 0:57 he replaces a...

In this short movie the guy explains the technology behind his 1kW LLC converter: https://youtu.be/wtcn6rZE1Eg At 0:57 he replaces a monolithic 16:2x1 transformer with 4 4:2x1 transformers, which is a basic matrix transformer technology. OK. At 1:50 he merges two U-shaped transformers into a single E core, still fine. At 2:04 I got lost. He removes the center leg of the E core, b...


High voltage transformer?

Started by Robert Baer in sci.electronics.design7 years ago 2 replies

Someone said they saw a large high voltage transformer out of its oil bath. Two or three fat "wire" turns on primary and 8-10 not as fat...

Someone said they saw a large high voltage transformer out of its oil bath. Two or three fat "wire" turns on primary and 8-10 not as fat "wire" turns on secondary. Translation is *thousands* of volts per turn, and nano-ohms impedance. Two impossible things together used to help power a city? Huh??


Temperature of CCFL transformer in laptop?

Started by Joerg in sci.electronics.design3 years ago 47 replies

A laptop backlight was turning off after a few minutes of work and, miracuslously, when turning the laptop off (invokes hibernate) it always...

A laptop backlight was turning off after a few minutes of work and, miracuslously, when turning the laptop off (invokes hibernate) it always came back on. I opened the screen, reseated the inverter connectors, so far it ran through more than an hour. Here's knocking on wood. However, I noticed that the transformer core on the CCFL inverter heats up to the point where leaving my finger o...


turns ratio

Started by John Larkin in sci.electronics.design10 years ago 127 replies

If I measure the voltage ratio of a 2-winding transformer, 1.0943 in this case, how might I determine the number of primary and...

If I measure the voltage ratio of a 2-winding transformer, 1.0943 in this case, how might I determine the number of primary and secondary turns? I recall a high-school math class where we were shown how to convert a real number into an integer ratio N/M somehow. It's a smallish audio-type transformer, Lp around a henry maybe, so there are probably not a huge number of turns. An onli...


modern flyback cross reference?

Started by -asop- in sci.electronics.design2 years ago 8 replies

I am looking into making a circuit that will essentially use a high current flyback transformer. I'd like to use the one...

I am looking into making a circuit that will essentially use a high current flyback transformer. I'd like to use the one here: https://www.amazing1.com/products/high-voltage-switching-transformer-4000-turn-coil-of-37-wire-4 0kv-30ma-15k-60khz-large-core.html However, after ordering from this firm in the past, after I received the part, I was able to find it online from a different firm a


Harmonics in pole power transformers?

Started by Joerg in sci.electronics.design6 years ago 141 replies

Folks, A system needs to be able to detect whether a pole transformer has failed and stopped feeding power to a pump. The transformer will be...

Folks, A system needs to be able to detect whether a pole transformer has failed and stopped feeding power to a pump. The transformer will be 100ft or more away. The detection has to work even without any power flow meaning we can only detect the presence of a 60Hz electric field that leaks from the various boxs such as a breaker box. In order not to get fooled by 60Hz from other ove...


Audio amp Mystery

Started by billbowden in sci.electronics.design5 years ago 10 replies

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...


Make your own Power Transformer

Started by Anonymous in sci.electronics.design3 years ago 33 replies

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)?


little pcb-mount CTs

Started by John Larkin in sci.electronics.design7 years ago 83 replies

Anybody know of a source for a small (1 amp range) PCB mount current transformer? Frequency will be around 400 Hz. There are switcher...

Anybody know of a source for a small (1 amp range) PCB mount current transformer? Frequency will be around 400 Hz. There are switcher current sense CTs, but I don't know if they will work that low. Or maybe I could use a shunt and a voltage-mode (audio) transformer. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlan...


E55 Ferrite transformer and Litz wire

Started by P E Schoen in sci.electronics.design5 years ago 27 replies

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...


Midcom Technical Note #82

Started by Simon S Aysdie in sci.electronics.design8 years ago 5 replies

Does anyone have a pdf of this? Midcom Technical Note #82 Midcom's Tips for Transformer Modeling by Dave LeVasseur 29-Jan-98 It is...

Does anyone have a pdf of this? Midcom Technical Note #82 Midcom's Tips for Transformer Modeling by Dave LeVasseur 29-Jan-98 It is referenced in /Midcom Transformer Theory/ by the same author (TN69). I suspect Midcom has been acquired by Wurth. I can't find it at Wurth. The closest I came is this: http://wenku.baidu.com/view/c8ffa8250722192e4536f6ee.html But I couldn't f...


Villard circuit and transformer question

Started by Daku in sci.electronics.design10 years ago 11 replies

Could some electronics guru provide some insight into the following ? One can use a Villard multiplier to step-up voltage and a...

Could some electronics guru provide some insight into the following ? One can use a Villard multiplier to step-up voltage and a capacitive divider to step-down voltage. However, most power supplies still use a transformer for voltage step-up/down. What is the inherent deficiency of a Villard circuit that prevents it from being used for these purposes. Thanks in advance for your feedback.


Devil's Staircase

Started by John Larkin in sci.electronics.design2 years ago 84 replies

I want to make a class-D audio amp, 150 watts or so, using a TI TPA3255 maybe. It's good for 600 watts mono! I'll use it full-bridge to...

I want to make a class-D audio amp, 150 watts or so, using a TI TPA3255 maybe. It's good for 600 watts mono! I'll use it full-bridge to drive a step-up transformer, probably a custom toroid. But toroids are especially unhappy with any DC drive, and the class D part will surely have some DC offset. The TI spec is 60 mV max output offset, which could be a problem into a good transformer....


transformer thermals

Started by Anonymous in sci.electronics.design1 year ago 54 replies

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...


How to wind a push-pull transformer?

Started by Piotr Wyderski in sci.electronics.design3 years ago 21 replies

I need to make a transformer for a push-pull converter. The core is a 25.3/14.8/10 toroid made of N87, f=200kHz (total, 100kHz per switch),...

I need to make a transformer for a push-pull converter. The core is a 25.3/14.8/10 toroid made of N87, f=200kHz (total, 100kHz per switch), Bmax=100mT, PRIMARY_Irms=10A, PRIMARY_V_MAX=20V. This gives 2x5 turns and this low value opens many options. 1. 5 turns, each turn close to one another, then the other 5 turns the same way. Pros: thin winding, short supply wires. 2. 5 turns across ...


Loading up a 36kW transformer

Started by Yzordderrex in sci.electronics.design8 years ago 21 replies

I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run= . I looked at having some inductors wound, but that was about $4k. ...

I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run= . I looked at having some inductors wound, but that was about $4k. I've l= ooked at custom load bank, also about $4k. I can run three electric water = heaters ($250.00 each)and discharge about 90 gals an hour of hot water. Th= e eagle glo-coils are not manufactured anymore - what a shame. I've looked= at immers...


1, 2 , 3

Started by Jan Panteltje in sci.electronics.design8 years ago 18 replies

And maybe you think software is difficult. It was also difficult ot fit this all in this solar flashlight box. The parts: ...

And maybe you think software is difficult. It was also difficult ot fit this all in this solar flashlight box. The parts: http://panteltje.com/pub/1_2_3_part_1_IMG_4342.JPG Battery, GPS, SDcard, OLED, GMtube, Speaker, Flashlight LEDs... HV transformer is on backside 'PCB'. Better view of HV transformer, things coming together: http://panteltje.com/pub/1_2_3_part_2_IMG_4344.JPG ...