some flyback switchers

Started by John Larkin in sci.electronics.design7 years ago 35 replies

I need maybe +750 volts at low current, 15 mA maybe. Here are some attempts to recover some of the leakage inductance energy and keep...

I need maybe +750 volts at low current, 15 mA maybe. Here are some attempts to recover some of the leakage inductance energy and keep the transformer affordable. https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Flybacks.JPG I got some quotes on PCB mountable HV bricks, and the prices were insane. Maybe I'll make my own, which is more fun anyhow. -- John Larkin ...


Galvanic isolation without transformers ??

Started by Anonymous in sci.electronics.design8 years ago 60 replies

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.


Distribution Transformer Manufacturer

Started by Servo Kon in sci.electronics.design10 years ago 1 reply

Since its inception in 1990, Servokon has left no stone unturned in becoming the best Industrial Servo Voltage Stabilizer Manufacturer in Delhi....

Since its inception in 1990, Servokon has left no stone unturned in becoming the best Industrial Servo Voltage Stabilizer Manufacturer in Delhi. We have manufactured our products to match the standards and changing requirements of our customer. To know more about us please visit: http://www.servokon.in/


Distribution Transformer Manufacturer

Started by Servo Kon in sci.electronics.design10 years ago 2 replies

Since its inception in 1990, Servokon has left no stone unturned in becoming the best Industrial Servo Voltage Stabilizer Manufacturer in Delhi....

Since its inception in 1990, Servokon has left no stone unturned in becoming the best Industrial Servo Voltage Stabilizer Manufacturer in Delhi. We have manufactured our products to match the standards and changing requirements of our customer. To know more about us please visit: http://www.servokon.in/


Switching Regulator

Started by John Smith in sci.electronics.design7 years ago 39 replies

I have a transformer which is rated at 12V AC, 1A I'd like to turn that into 5V at up to 2A, or a little less than 2A if there's not enough...

I have a transformer which is rated at 12V AC, 1A I'd like to turn that into 5V at up to 2A, or a little less than 2A if there's not enough margin. What's the best switching regulator chip to use with easily available peripheral components? And preferably in a DIP package. This is a one time build so I don't need super low cost. I'm not unable to search google, digikey etc myself bu...


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...


OT: Cryptic writings

Started by bitrex in sci.electronics.design8 years ago 10 replies

Can anyone decipher what these mean? They're on the sidewalk at the apartment complex my father lives...

Can anyone decipher what these mean? They're on the sidewalk at the apartment complex my father lives in: https://www.dropbox.com/s/bugki0amcoxa784/20141214_160457.jpg?dl=0 They're on the sidewalk near this transformer(?) enclosure. There was an explosion in it over the summer which knocked out power and set off fire alarms throughout the complex. I guess they did an interim rep...


Need 6V ballast for 9W CFL

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

Does anyone know where I might get a ballast to drive a 9W CFL tube (germicidal lamp) from a 6V source? There are a number of good circuits...

Does anyone know where I might get a ballast to drive a 9W CFL tube (germicidal lamp) from a 6V source? There are a number of good circuits around, but all require a custom-wound transformer, which would be difficult for me. A bare circuit board is fine. Don't want it enclosed in a metal case. I need 10 of these things. Thanks in advance. Steve


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


Replacing a transformer with opamps

Started by George Herold in sci.electronics.design11 years ago 15 replies

I=92ve been mucking about with double balanced mixers. I wanted something to work below 100kHz, so I ordered a few audio transformers. They...

I=92ve been mucking about with double balanced mixers. I wanted something to work below 100kHz, so I ordered a few audio transformers. They worked fine, but it seemed to me that you should be able to replace the transformers with some opamps. I bashed my head against the wall* for a day or so trying to come up with a circuit of my own. Today I went searching online and found this idea from...


My first flyback, Help!

Started by George Herold in sci.electronics.design4 years ago 42 replies

Hi all, well I went and moded JL's flyback with the LTC3803. I stuck the file in dropbox, but if someone can't access that I'll be happy to...

Hi all, well I went and moded JL's flyback with the LTC3803. I stuck the file in dropbox, but if someone can't access that I'll be happy to copy it here. https://www.dropbox.com/s/gd4zngedu9za4dc/GH_flyback_2.asc?dl=0 For the inductor I picked one of the Versa-Pak inductors with 6 coils on one form. And made a 1:5 transformer. So I first assumed I'd be running in continuous conduct...


Wanted: Boonton 91-B Schematic

Started by amdx in sci.electronics.design8 years ago 3 replies

Hi guys, I'm looking for the schematic of a Boonton 91-B RF Voltmeter. I can find many other 91 series schematics but not the 91-B. It would...

Hi guys, I'm looking for the schematic of a Boonton 91-B RF Voltmeter. I can find many other 91 series schematics but not the 91-B. It would make my job easier with the correct schematic. Any leads? Thanks, Mikek P.S. To Jeff, This is a tube model, I heeded your advice, I'm using an isolation transformer. problem; I have one calibration pot (1V range) that has very...


Transformer Turns Question

Started by Chris in sci.electronics.design6 years ago 20 replies

Hi guys, I need to count the number of turns of wire on this relay core I have. Trouble is, there are way too many to do so manually. The DC...

Hi guys, I need to count the number of turns of wire on this relay core I have. Trouble is, there are way too many to do so manually. The DC resistance is over 500 ohms and the wire gauge is *very* tiny; there must be a couple of thousand turns at least. I've thought of an ingenious way of counting them and I'd like to know if it will work in practice. What I plan to do is wind say 1...


Power supply topology question ...

Started by Anonymous in sci.electronics.design9 years ago 18 replies

Could some electronics guru please shed some light on the following. The standard topology for a linear regulated power supply is basically...

Could some electronics guru please shed some light on the following. The standard topology for a linear regulated power supply is basically as follows: isolation step-down transformer | v rectifier(bridge or 2 - diode) | v capacitor ripple filter bank | v voltage regulator ...


Connector ID?

Started by Phil Hobbs in sci.electronics.design3 years ago 2 replies

Hi, all, I have this very nice Mitutoyo FS-110 metallurgical microscope with a slightly mismatched lamp housing (wrong connector). It works...

Hi, all, I have this very nice Mitutoyo FS-110 metallurgical microscope with a slightly mismatched lamp housing (wrong connector). It works okay with a separate DC power supply, but I'd much rather use the variable transformer built into the microscope base. Mitutoyo uses connectors like these, which I have never seen anywhere else. They're sort of like a cross between DIN and Cann...


SMPS Topologies

Started by Cursitor Doom in sci.electronics.design5 years ago 62 replies

Gentlemen, What's the exact technical term for the switcher topology where you only have one large toroidal (typically) transformer right at...

Gentlemen, What's the exact technical term for the switcher topology where you only have one large toroidal (typically) transformer right at the mains entry point which takes line AC and outputs it at a lower voltage level whereupon it's fed into the bridge rectifier and thence into a large storage cap whereupon it can be chopped up, regulated and finally filtered, there being no othe...


small high frequency mosfets

Started by mook johnson in sci.electronics.design10 years ago 4 replies

gents, I'm looking for a high sped, low capacitance mosfet in a package the size of a to-92 or smaller than a SOIC-8 with the following...

gents, I'm looking for a high sped, low capacitance mosfet in a package the size of a to-92 or smaller than a SOIC-8 with the following characteristics. application: Attached to a 1:1 push pull transformer with 5V on the CT to generate ~ 10V p-p on the output. This means the switching transistors will see at least 10V when the other one is one + leakage inductance spike. Each tr...


Transistor Phase Inverter Values

Started by Anonymous in sci.electronics.design9 years ago 87 replies

I have a complex low frequency signal from which I need to produce two outputs of equal amplitude but inverted in phase. I would prefer not to...

I have a complex low frequency signal from which I need to produce two outputs of equal amplitude but inverted in phase. I would prefer not to use a transformer due to size. Here is the circuit I am considering. http://www.4shared.com/photo/CDpvTMJW/43_1_Large_Signal_Amplifiers.html This is low current, so I would just use a BC547 or the like. Can anyone please tell me how to prope...


Irrigation valves - anybody use one?

Started by mkr5000 in sci.electronics.design7 years ago 11 replies

I know it's off topic a bit but this is my go to group for real answers. Have any of you guys messed with inline irrigation valves? I never have...

I know it's off topic a bit but this is my go to group for real answers. Have any of you guys messed with inline irrigation valves? I never have and have a new Rainbird valve that needs 24vac so I simply connected it to a 24vac (20va) control transformer I had and the solenoid chatters like crazy, so quickly disconnected it. (Usually when I hear chatter it means a need for DC but th