Differential and Common Mode Noise Differential and Common Mode Noise 26
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Filtering and Suppressing Transients
Another EMC resource from EMC Standards EMC techniques in electronic design Part 3 - Filtering and Suppressing Transients Helping you solve your EMC problems 9 Bracken View, Brocton, Stafford ST17 0TF T:+44 (0) 1785 660247 E:[email protected] Design Techniques for EMC Part 3 — Filtering and Suppressing Transients Originally published in the EMC Compliance Journal in 2006-9, and available from http://www.compliance-club.com/KeithArmstrong.aspx Eur Ing Keith Armstrong CEng MIEE MIEEE Partner, Cherry Clough Consultants, www.cherryclough.com, Member EMCIA Phone/Fax: +44 (0)1785 660247, Email: [email protected] This is the third in a series of six articles on basic good-practice electromagnetic compatibility (EMC) techniques in electronic design, to be published during 2006. It is intended for designers of electronic modules, products and equipment, but to avoid having to write modules/products/equipment throughout – everything that is sold as the result of a design process will be called a ‘product’ here. This series is an update of the series first published in the UK EMC Journal in 1999 [1], and includes basic good EMC practices relevant for electronic, printed-circuit-board (PCB) and mechanical designers in all applications areas (household, commercial, entertainment, industrial, medical and healthcare, automotive, railway, marine, aerospace, military, etc.). Safety risks caused by electromagnetic interference (EMI) are not covered here; see [2] for more on this issue. These articles deal with the practical issues of what EMC techniques should generally be used and how they should generally be applied. Why they are needed or why they work is not covered (or, at least, not covered in any theoretical depth) – but they are well understood academically and well proven over decades of practice. -
Class-E Audio Modulated Tesla Coil Instruction Manual
Class-E Audio Modulated Tesla Coil CCllaassss--EE AAuuddiioo MMoodduullaatteedd TTeessllaa CCooiill IInnssttrruuccttiioonn MMaannuuaall Eastern Voltage Research, LLC May 19, 2017 REV F − 1 − http://www.EasternVoltageResearch.com Class-E Tesla Coil Instruction Manual Class-E Audio Modulated Tesla Coil BOARD REVISION C This manual only applies to the new Revision C PCB boards. These boards can be identified by their red or green silkscreen color as well as the marking SC2076 REV C which is located underneath the location for T41 on the upper right of the PCB board. May 19, 2017 REV F − 2 − http://www.EasternVoltageResearch.com Class-E Tesla Coil Instruction Manual Class-E Audio Modulated Tesla Coil AGE DISCLAIMER THIS KIT IS AN ADVANCED, HIGH POWER SOLID STATE POWER DEVICE. IT IS INTENDED FOR USE FOR INDIVIDUALS OVER 18 YEARS OF AGE WITH THE PROPER KNOWLEDGE AND EXPERIENCE, AS WELL AS FAMILIARITY WITH LINE VOLTAGE POWER CIRCUITS. BY BUILDING, USING, OR OPERATING THIS KIT, YOU ACKNOWLEDGE THAT YOU ARE OVER 18 YEARS OF AGE, AND THAT YOU HAVE THOROUGHLY READ THROUGH THE SAFETY INFORMATION PRESENTED IN THIS MANUAL. THIS KIT SHALL NOT BE USED AT ANY TIME BY INDIVIDUALS UNDER 18 YEARS OF AGE. May 19, 2017 REV F − 3 − http://www.EasternVoltageResearch.com Class-E Tesla Coil Instruction Manual Class-E Audio Modulated Tesla Coil SAFETY AND EQUIPMENT HAZARDS PLEASE BE SURE TO READ AND UNDERSTAND ALL SAFETY AND EQUIPMENT RELATED HAZARDS AND WARNINGS BEFORE BUILDING AND OPERATING YOUR KIT. THE PURPOSE OF THESE WARNINGS IS NOT TO SCARE YOU, BUT TO KEEP YOU WELL INFORMED TO WHAT HAZARDS MAY APPLY FOR YOUR PARTICULAR KIT. -
Chapter 6 BUILDING a HOMEBREW
1. Chapter 6, Harris CRYSTAL SETS TO SIDEBAND © Frank W. Harris 2002 Chapter 6 BUILDING A HOMEBREW QRP Among the guys I work, QRPs seem to be the most common homebrew project, second only to building antennas. Therefore this chapter describes a simple QRP design I have settled on. I use my QRPs as stand-alone transmitters or I use them to drive a final amplifier to produce higher power, 25 to 100 watts. It’s true that before you build a transmitter you’ll need a receiver. Unfortunately, a good selective, all-band ham receiver is complicated to build and most guys don’t have the time and enthusiasm to do it. (See chapter 13.) The next chapter describes building a simple, 5 transistor 40 meter receiver which I have used with the QRP below to talk to other hams. This simple receiver will work best during off hours when 40 meters isn’t crowded. It can also be used to receive Morse code for code practice. A 40 meter QRP module. The QRP transmitter above is designed exclusively for 40 meters, (7.000 to 7.300 MHz.) The twelve-volt power supply comes in through the pig-tail wire up on the right. The telegraph key plugs into the blue-marked phono plug socket on the right of the aluminum heat sink. The antenna output is the red-colored socket on the left end of the heat sink. The transmitting frequency of the QRP module is controlled by a quartz crystal. That’s the silver rectangular can plugged into the box on the right front. -
Soft Ferrites Applications
Ferroxcube Soft Ferrites Applications APPLICATIONS Material requirements: Introduction • Low losses • Defined temperature factor to compensate temperature Soft ferrite cores are used wherever effective coupling drift of capacitor between an electric current and a magnetic flux is required. They form an essential part of inductors and • Very stable with time. transformers used in today’s main application areas: Preferred materials: 3D3, 3H3. • Telecommunications • Power conversion INTERFERENCE SUPPRESSION • Interference suppression. Unwanted high frequency signals are blocked, wanted signals can pass. With the increasing use of electronic The function that the soft magnetic material performs may equipment it is of vital importance to suppress interfering be one or more of the following: signals. FILTERING Material requirements: Filter network with well defined pass-band. • High impedance in covered frequency range. High Q-values for selectivity and good temperature Preferred materials: 3S1, 4S2, 3S3, 3S4, 4C65, 4A11, stability. 4A15, 3B1, 4B1, 3C11, 3E25, 3E5. andbook, halfpage handbook, halfpage U1 U2 load U attenuation U1 (dB) U2 frequency frequency MBW404 MBW403 Fig.1 Filter application. Fig.2 Suppression application. 2008 Sep 01 17 Ferroxcube Soft Ferrites Applications DELAYING PULSES STORAGE OF ENERGY The inductor will block current until saturated. Leading An inductor stores energy and delivers it to the load during edge is delayed depending on design of magnetic circuit. the off-time of a Switched Mode Power Supply (SMPS). Material requirements: Material requirements: • High permeability (µi). • High saturation level (Bs). Preferred materials: 3E25, 3E5, 3E6, 3E7, 3E8, 3E9. Preferred materials: 3C30, 3C34, 3C90, 3C92, 3C96 2P-iron powder. U U handbook, halfpage 1 handbook, halfpage1 U2 U2 SMPS load delay U U U1 U2 U1 U2 time time MBW405 MBW406 Fig.3 Pulse delay application. -
Using Ferrite Beads Keep RF out of TV Sets, Telephones, VCR's Burglar Alarms and Other Electronic Equipment
Using Ferrite Beads Keep RF Out of TV Sets, Telephones, VCR's Burglar Alarms and other Electronic Equipment RFI and TVI have been with us for a long time. Now we have microwave ovens, VCR's and many other devices that do wrong things when they pick up RF. There are several ways to tackle the problem but most of them involve opening the affected equipment and adding suppressor capacitors, filters, and other circuit modifications. Unfortunately there is a serious disadvantage associated with this approach. Any modifications made to domestic entertainment equipment can - and often are - blamed for later problems that arise in it. Modifying your own equipment is not so bad, but taking a soldering iron to your neighbor's stereo is risky. An alternative approach is to use ferrite beads to reduce the amount of RF entering the equipment. If the equipment is in a metal box, or even if it's in a plastic box, if RF is prevented from entering the box on the antenna lead, the power cable, the speaker leads, the phono pickup leads, and on any other wires entering the box, it is possible to solve the problem without any modification to the equipment. Ferrite beads just slip over the wires and stop RF from going in. Ferrite beads are made of the same materials as the toroid cores used in broadband transformers but are used at much higher frequencies. For example, ferrite Mix 43 is used for tuned circuits in the frequency range 0.01 to 1 MHz. It is efficient and losses are low. -
Common Mode Chokes by Würth Elektronik
Welcome! Inductors & EMC-Ferrites Basics - Parts and Applications Wurth Electronics Inc. Field Application Engineer Michael Eckert Würth Elektronik eiSos © May/2006 Michael Eckert What is an Inductor ? technical view: a piece of wire wounded on something a filter an energy-storage-part (short-time) examples: Würth Elektronik eiSos © May/2006 Michael Eckert What is an EMC-Ferrite ? Technical view: Frequency dependent filter Absorber for RF-energy examples: EMC Snap-Ferrites EMC-Ferrites for SMD-Ferrites Flatwire Würth Elektronik eiSos © May/2006 Michael Eckert Magnetic Field Strenght H of some configurations I long, straight wire H = 2⋅π ⋅R N⋅I Toroidal Coil H = 2⋅π ⋅R N⋅I Long solenoid H = l (e.g. rod core indcutor) Würth Elektronik eiSos © May/2006 Michael Eckert Example: Conducted Emission Measurement • Dosing pump for chemicals industry. Würth Elektronik eiSos © May/2006 Michael Eckert Conducted Emission Measurement • Power supply V 1.0 PCB Buck Converter ST L4960/2.5A/fs 85-115KHz Würth Elektronik eiSos © May/2006 Michael Eckert Conducted Emission Measurement • Power supply V 1.1 PCB Schematic Würth Elektronik eiSos © May/2006 Michael Eckert Awareness: • Select the right parts for your application • Do not always look on cost Very easy solution with a dramatic result!!! or Choke before Choke after Würth Elektronik eiSos © May/2006 Michael Eckert What is permeability [ur]? – Permability (µr): describe the capacity of concentration of the magnetic flux in the material. typical permeabilities [µr] : Magnetic induction in ferrite: -
Custom Power Supplies, Transformers, Chokes & Reactors
YOUR POWER SOURCE Custom Power Supplies, Transformers, Chokes & Reactors NeeltranThe Story Transformers and Power Supplies • Industry Leader since 1973 Neeltran has become the most reliable supplier of Transformers and Power Supply Systems in the industry. Our engineers, along with our manufacturing team, have the knowledge and ability to meet the special needs of our customers. All power supplies are custom designed to your specifications by our engineering staff and completely fabricated in-house at our manufacturing facility. Our facilities and experience include: • Research & Development Since 1973 Neeltran has been a leading • Test Laboratory manufacturer of transformers and • Design Engineering power supplies. • Printed Circuit Board Manufacturing Our general product range is: • Steel Cutting Machinery • Dry Type and Water Cooled Transformers: • Baking Ovens 5–10,000 KVA (up to 25 KV input) • Vacuum Pressure Impregnation Tanks (Outputs up to 300 KV and 50 KHZ) • Coil Winding Equipment • Oil filled Transformers (Rectifier type only): 100 KVA to 50 MVA (up to 69 KV input) • Painting and Steel Fabrication to manufacture our own enclosures • Oil filled high frequency Transformers: • Assembly Areas up to 50 KHZ, 2000 KVA, up to 50 KV output Industry standards are maintained with our • Cast Coil Transformers: up to 20 MVA testing equipment assuring that all shipped (up to 35 KV input) products meet customer’s requirements and • Chokes and Reactors air or iron: specifications. Impulse testing as well as customer up to 25 KV, 20,000 amps specific testing is available upon request. • Power Supplies: 100 A to 500,000 amp (AC or DC) 1500 VDC. Special outputs up to 300,000 volts AC or DC and high frequencies are available. -
Checking out the Power Supply the Power Supply Must Be Carefully Checked out a Good Many Australian-Made Sets from the Mid 1930S-1950 Era
Checking out the power supply The power supply must be carefully checked out a good many Australian-made sets from the mid 1930s-1950 era. Fig.1 before switching on a vintage radio. The shows a typical circuit configura- components most likely to be at fault are the tion but there are other variations. electrolytic capacitors, most of which should be For example, some rectifiers re- quire a cathode voltage of 6.3V AC, replaced as a matter of course. not 5V. Similarly, not all radio valves use Although only a few parts are in- (equivalent to 570 volts, centre- 6.3V heater supplies. There are volved, the power supply is a com- tapped). 2.5V valves, 4V valves and 12V mon source of problems in vintage The 5V and 6.3V AC supplies are valves in some late model sets. In radios. It should be carefully check- wired straight from the trans- these radios, the low tension ed out before power is applied, as a former to the filaments and voltages on the transformer will be fault here can quickly cause heaters. However, the high tension different — but that's about all. damage to critical components. supply must be rectified to give a The high tension voltage will still be Most mains-operated valve high-tension DC supply for the well in excess of 250 volts. radios have three separate secon- anodes and screens for the various The output from the rectifier dary windings on the power receiving and output valves. A valve will not be pure DC but does transformer. -
Designing Magnetic Components for Optimum Performance Article
Power Supply Design Seminar Designing Magnetic Components for Optimum Performance in Low-Cost AC/DC Converter Applications Topic Category: Magnetic Component Design Reproduced from 2010 Texas Instruments Power Supply Design Seminar SEM1900, Topic 5 TI Literature Number: SLUP265 © 2010, 2011 Texas Instruments Incorporated Power Seminar topics and online power- training modules are available at: power.ti.com/seminars Designing Magnetic Components for Optimum Performance in Low-Cost AC/DC Converter Applications Seamus O’Driscoll, Peter Meaney, John Flannery, and George Young AbstrAct Assuming that the reader is familiar with basic magnetic design theory, this topic provides design guidance to achieve high efficiency, low electromagnetic interference (EMI), and manufacturing ease for the magnetic components in typical offline power converters. Magnetic-component designs for a 90-W notebook adapter and a 300-W ATX power supply are used as examples. Magnetic applications to be considered include the input EMI filter, power inductor design, high-voltage (HV) level-shifting gate drives, and single- and multiple-output forward-mode transformers in both wound and planar formats. The techniques are also applied to flyback “transformers” (coupled inductors) and will enable lower- profile designs with lower intrinsic common-mode noise generation. I. IntroductIon Gate Drive Note: The SI (extended MKS) units system AC Filter PFC Isolated Main Drive (for some Converter Output(s) is used throughout this topic. CM Inductor, topologies), Balanced Bridge, Differential This material is intended as a high- PFC Inductor, Multi-Output Filter level overview of the primary consider- Bias Flyback ations when designing magnetic components for high-volume and cost- Isolated Feedback optimized applications such as computer Fig. -
APPLICATION NOTE How to Select the Right Reinforced Transformer for High Voltage Energy Storage Applications
APPLICATION NOTE How to Select the Right Reinforced Transformer for High Voltage Energy Storage Applications Introduction Providing isolated low voltage bias power to ICs such as microcontrollers, analog-to-digital HCT Series converters, isolated gate drivers or voltage monitoring ICs in high voltage systems is usually accomplished with an isolated DC-DC converter. If the high voltage system is spread out over several modules, the architecture may call for a parallel DC bus on the low voltage side with multiple isolated low power DC-DC converters for each module. Because it is used multiple times in this scenario, an efficient and cost-effective topology is the best approach. This application note highlights the design benefits of using push-pull transformers that are proven solutions for these situations. Used as an example is the Bourns® Model HCTSM8 series transformer, which is AEC-Q200 compliant and available with a wide range of turns ratios as standard. Multiple turns ratios are an important feature enabling the same basic circuit topology to be replicated across a system with the same components and PCB layout. With a transformer series like the Model HCTSM8, designers are able to select the right reinforced transformer part number based on the specified output voltage for powering a microcontroller or an isolated IGBT gate driver. www.bourns.com 07/20 • e/IC2075 APPLICATION NOTE How to Select the Right Reinforced Transformer for High Voltage Energy Storage Applications Why Push-Pull Transformers are an Optimal Choice Electrical Advantages HCT Series Push-pull transformers are known to operate well with low voltages and low variations in input and output. -
Measured Data for Chokes Wound on New Big #31 Toroid
A New Choke Cookbook for the 160–10M Bands Using Fair-Rite #31 2.4-in o.d. (2631803802) and 4-in o.d. (2631814002) Toroids © 2018-19 by James W. Brown All Rights Reserved Introduction: Common mode chokes are added as series elements to a transmission line to kill common mode current. The line may be a short one carrying audio or control signals between a computer and a radio, video between a computer and a monitor, noisy power wiring, or feedlines for antennas. This application note focuses on the use of chokes on the feedlines of high power transmitting antennas to suppress received noise, to minimize RF in the shack (and a neighbor’s living room) and to minimize crosstalk between stations in multi-transmitter environments. Fundamentals Differential mode current is the normal transmission of power or other signals inside coax, or between paired conductors. The currents in the two conductors are precisely equal and are out of polarity (that is, flowing in opposite directions at each point along the line). Because the current in the two conductors are equal and out of polarity, they do not radiate, nor do they receive. Common mode current is carried on the outside of the coax shield, or as the difference of unequal currents on the two conductors of 2-wire line. A line carrying common mode current acts as antenna for both transmit and receive. Common mode current that couples to the antenna changes the directional pattern of an antenna by filling in the nulls of it’s directional pattern. -
Chapter 21 Some Aspects of the Balun Problem
Chapter 21 Some Aspects of The Balun Problem (Adapted from QST, March 1983) type baluns which prove that with a 50-ohm resis• tive load, the transformers in typical 1:1 or 4:1 Sec 21.1 Introduction baluns do not yield a true 1:1 or 4:1 impedance transfer ratio between their input and output termi• nals. This is because of losses, leakage reactance, hy all the mystery surrounding baluns? and less than optimum coupling. My findings have Here's some straight talk to dispel the been substantiated by the work of the late John rumors! The balun—to use, or not to W Nagle, K4KJ (Ref 80). Furthermore, the imped• use—is one of the hottest topics in amateur radio. ance-transfer ratio of such baluns degrades even Because certain aspects of the connection between a further when used with an antenna that is reactive coaxial feed line and a balanced antenna have been from operation away from its resonant frequency. ignored, misunderstanding still exists concerning This degradation of impedance transfer associated the function of baluns. Many commercial baluns with transformer-type baluns poses no serious embody some form of impedance transformer, pro• operational problems. However, SWR curves plot• moting our tendency to misconstrue them as little ted from measurements of an antenna using such a more than a matching device, while their primary balun differ significantly from those using a choke function is to provide proper current paths between balun that has no impedance-transfer error. Thus, balanced and unbalanced configurations. when a precision bridge is used to measure anten• To help clarify the misunderstanding, this chap• na impedance (R + y'X), the data will be erroneous ter explains some of the undesirable effects that with either a transformer-type balun in the circuit, occur when a balun is not used, and some that or with no balun at all.