Stripline capacitance calculator. Choose a calculator to tune your PCB design.

Stripline capacitance calculator Fill in the relative permittivity of the dielectric and the trace width, thickness and distance to each plane. Mar 1, 1998 · calculate the pcb impedabce and capacitance of asymmetric stripline It appears that you are using AdBlocking software. A microstrip is a type of transmission line in which a strip of a conducting material like copper is mounted on a dielectric material and routed to a ground plane. Choose Type. Figure \(\PageIndex{2}\): Fringe capacitance at the corners of the strip in a stripline transmission lines. Characteristic capacitance of a stripline Characteristic capacitance of a stripline Delay constant of stripline Mar 1, 1998 · calculate the pcb impedabce and capacitance of dual stripline It appears that you are using AdBlocking software. The impedance of the stripline is measured in Ohms and can be determined using this calculator. 0. Pasternack's Stripline Impedance Calculator uses the dimensions of the stripline, as well as the dielectric constant, to compute the characteristic impedance. 6. Different methods were used to support the center strip, but in all cases the region between the two outer plates was filled with only one single medium, either dielectric material or air. Understanding Symmetric Stripline Impedance: Symmetric Stripline Configuration :A flat conductor with the same spacing between it and each ground plane is positioned between two ground planes Stripline Stripline Impedance Calculation: To calculate the impedance of stripline stripline, factors such as the geometry of the line and the dielectric constant are taken into account. Increasing W decreases Zo. Calculate the impedance of PCB traces quickly and easilly using DigiKey's Trace Impedance Calculator. e. Overview. Providing accurate and efficient impedance calculations simplifies the design process, reduces errors, and ensures that the final product meets performance requirements. You won’t be able to compute signal losses without performing an impedance calculation. runs gmsh to create a new surface mesh for a PCB stripline with thickness T. A complete range of radio frequency calculators, including metric-standard, link budget, coax cable, power, attenuation, frequency and plenty others, provide you with the correct figures that you need for all your RF, microwave and Dec 30, 2023 · With over 300 calculators covering finance, health, science, mathematics, and more, GEG Calculators provides users with accurate and convenient tools for everyday calculations. This calculator is designed to provide accurate impedance assessments for various edge-coupled stripline configurations. Stripline Impedance Calculator. This free coplanar waveguide (CPW) calculator calculates the optimal width of a waveguide line for a given characteristic impedance (Z 0), based in the substrate geometry. Description The inductance calculated using this tool is the external inductance the loop bounded by the wire pair over the wire length, circular wire. Synthesize Aug 10, 2023 · Therefore, they require a slight variation of the stripline characteristic impedance. Description Inductance calculated using this tool is the internal inductance of a straight, circular wire. Synthesize Stripline Impedance Calculator Provide values for three of the four parameters h, t, w, Z 0 and the relative permittivity of the dielectric. Microstrip (outer layer) impedance. The substrate parameters (ε r and h) are required. View Notes. Rho: Conductor resistivity relative to copper. Following is the list of useful converters and calculators. 109-115, November 1989. Usually this would be simulated with software but as a first approximation you should use the capacitance of a two wire line. Fig. The Calculator Calculates the values of the Characteristic Impedance, Capacitance per unit length and propogation speed. Description The inductance calculated using this tool is the inductance of the loop bounded by the two biplanar flat conductors. Note: Units do not matter for this calculation as long as they are consistent. 7 mil w = 4 mil s = 9 mil h1 = 4 mil h2 = 5 mil Er = 3. 0808908 / Calculations provided on this page are a simplified subset from EMI Analyst models. Select the dimension unit of the stripline: mm mils Separation between Planes Aug 21, 2023 · A Stripline Impedance Calculator is an indispensable tool for engineers and designers working on high-frequency and high-speed PCB designs. A Mitered bend reduces some of that capacitance, restoring the line back to it's original characteristic impedance. Microstrip and stripline capacitance. The cost of running this website is covered by advertisements. 5. May 22, 2022 · Figure \(\PageIndex{1}\): Stripline transmission lines. 119-126. These are pre-defined topologies, such as shown in Figure 1. 18 pF/cm. The trace capacitance is defined with respect to the nearest ground plane in the particular configuration presented above. Assumptions and Limitations The characteristic impedance of a stripline was evaluated using conventional methods like finite difference method, and method of moments by solving the Poisson’s equation for the capacitance and hence finding Z0. Click here to go to our stripline calculator. By determining its trace resistance, the contribution of a microstrip to the overall circuit resistance can be evaluated. Enter the separation distance. W/(H-T) 0. As noted above, the foregoing equations are valid only over a limited range because of the assumption depicted in Figure 2. Characteristic impedance of a stripline. Conditions (weak microstrip mode, low side Dec 29, 2019 · Stripline Impedance Equation. Choose the units of measurement. Adding series capacitance moves counter-clockwise along constant resistance circles; Adding shunt inductance moves clockwise along constant admittance circles; Adding shunt capacitance moves counter-clockwise along constant admittance circles; Use the Series and Shunt Impedance Calculator: to try your own impedances; Change Grid: A three-dimensional capacitance calculator is used for the accurate calculation of the per-unit-length capacitance matrix of flaring, multiple, coupled microstrip and stripline interconnections. Verified with Agilent LineCalc and Agilent Momentum simulations. Calculates the capacitance of a circular pair of conductors in a homogeneous medium. The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001. 2. The higher the value, the larger the loss. Click the button corresponding to the unknown parameter to calculate its value. sh; For each thickness value T in the file TFile, this script. This calculator is designed to calculate the characteristic impedance of a symmetric stripline - a flat conductor between two ground planes whose distance between the conductor and the planes is the same for both reference planes. Oct 18, 2016 · So compute Zo from a coplanar stripline calculator (complex) then compute C from Zo as shown here. Apr 25, 2011 · This nice online calculator assists in solving impedance calculations with parallel and serial combinations of passive components. Additionally, you can also obtain information such as capacitance, propagation delay, and inductance associated with the stripline using this calculator. A Grounded CPW transmission line calculator. A symmetric stripline is constructed equidistantly between two plane layers, Stripline Z o Calculator Capacitance (C): 1. Broadside Z o Calculator Capacitance (C): 1. You can also choose to fill in the desired characteristic impedance and leave one of the trace parameters blank. Adding series capacitance moves counter-clockwise along constant resistance circles; Adding shunt inductance moves clockwise along constant admittance circles; Adding shunt capacitance moves counter-clockwise along constant admittance circles; Use the Series and Shunt Impedance Calculator: to try your own impedances; Change Grid: Nov 11, 2013 · Hi all, I'm using asymmetric stripline for differentail traces and I want to calculate the capacitance The stack-up is as below: t = 0. Many conductor properties are frequency dependent and dynamically affect electromagnetic characteristics of circuitry and systems. The below PCB Calculator helps you to calculate the impedance, capacitance, propagation delay and inductance of a Microstrip Line PCB . Description The inductance calculated using this tool is the external inductance of the loop bounded by the flat conductor and the ground plane. 035 mm; How to Calculate PCB Trace-to-Plane Capacitance Dec 11, 2024 Repalced internal (hard codeed) conductor trapazoid shape adjustment with settabe percentage in options Updated asymetric stripline calculator formula to Brian C. Description The inductance calculated using this tool is the external inductance of the loop bounded by the wire and the ground plane over the wire length. 063″ thick? The formula for capacitance of two planes is: Using 4. Press Calculate. Circular Parallel Plate Capacitance; Wire Pair Resistance; Wire Over Ground Plane Resistance; Coplanar Resistance; Microstrip Resistance; Stripline Resistance Coplanar Inductance Model Inductance of the loop bounded by two coplanar flat conductors is: Units: Henries. Capacitance Calculators. The free impedance calculator shown below can help you determine the correct width needed to hit a target impedance. Calculates the capacitance of coplanar conductors embedded in a homogeneous dielectric medium. The impedance value is determined using special formulas and graphs. The microstrip and stripline structures are available for free to any visitor after a brief registration. Enter the area of one plate. Coplanar Waveguide Analysis/Synthesis Calculator. Circular Parallel Plate Capacitance; Wire Pair Resistance; Wire Over Ground Plane Resistance; Coplanar Resistance; Microstrip Resistance; Stripline Resistance Capacitance Calculators. Jul 3, 2024 · There are several PCB impedance calculator tools available, ranging from simple web-based calculators to advanced simulation software. where C air represents the capacitance of the trace in the atmosphere instead of the substrate. At low frequencies, where skin depth is greater than conductor width and thickness is greater than ground plane thickness, ac resistance is approximately the same as the dc resistance. Mar 10, 2022 · The free version allows calculation of simple single-ended and differential microstrip and stripline structures. Therefore, it has just one environment surrounding it. 8 Length = 15 cm ~= 600 mil There is someone who know how to calculate the capacitance please The IPC-2141 equations provide a capacitance per unit length equation that can be used to calculate the PCB trace inductance. Calculate. Barrett in the 1950s. 35; 2. Welcome to our Edge-Coupled Stripline Impedance Calculator, your essential tool for calculating the impedance of edge-coupled striplines in PCBs based on specific operational parameters. Click the button corresponding to the unknown parameter to calculate its value ( w/(h-t) <0. Use Stripline Impedance Calculator to find the PCB Impedance, capacitance, propagation delay and inductance To calculate the signal loss for the chosen impedance model, you need to click on the Signal Loss Calculator tab. A stripline routes on the inner layers of a circuit board. Model accounts for proximity effect of a wire close to ground plane. 25; 1 < ε r <15 ). Returns mutual inductance, M, and mutual capacitance, C m. This calculator is designed to calculate the characteristic impedance of an edge coupled stripline. Such a microstrip is constructed with two traces referenced to the same reference plane with a dielectric material between them. Cohn, Seymour B. The substrate parameters (ε r and h) and the frequency of interest are required. The capacitance formed between the underside of the trace and plane, Cpp. com Acknowledgements. Description The capacitance calculated using this tool is the capacitance between a flat conductor and the ground plane over the conductor length. Calculates the capacitance of conductive circular parallel plates in a homogeneous dielectric medium. This parameter is used for the loss calculations. What is the total capacitance in a long trace on a board, 10 inches long? Next rule of thumb: RoT #6: The loop inductance per length of all 50 Ohm transmission lines. 25 inches long? 2. Wadell formula. Biplanar Inductance Model Inductance of the loop bounded by two biplanar flat conductors is: Units: Henries. Capacitance calculations would then use an applied voltage and a Coulombmeter to measure the charge and calculate the total Difference between a Microstrip Line and a Stripline in a Circuit Board. Capacitance: Input Values: Area: Separation distance: Number: Dielectric Constant: References: The ARRL Handbook for Radio Communications To use the calculator: 1. Capacitance calculator for stripline conductors. To our valued customers please note that our offices and warehouses will be closed on the following date, December 25th, 2024 for the Christmas Holiday. Resistance calculated using this tool includes both dc and ac resistance of stripline conductors. Capacitance vs. Enhance your understanding of the electrical transmission line’s attributes and optimize your circuit design accordingly. 6193 Dual Stripline Impedance Calculator. Stripline, according to David Pozar's textbook "Microwave Engineering" was invented at by R. Nevertheless, it is still useful for ballpark estimates. Acknowledgements: The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001. . Ls = 10. Pasternack online RF calculators , conversions and formulas are well suited for radio frequency designers and engineers who need answers to complex RF questions. 4. Figure 1. Purpose of Algorithm To calculate mutual inductance and capacitance of coupled lines Basic Description of Algorithm The subroutine identifies the configurations and calculates the mutual inductance and A broadside coupled stripline is constructed between two reference planes. Select the Zo button to calculate the characteristic impedance of the trace. T/H 0. Dec 8, 2023 · How to Calculate Parasitic Capacitance? The figure below shows example calculations for an Isola 370HR laminate with 50Ω CPW microstrip and stripline. Choose a calculator to tune your PCB design. Mar 1, 1998 · calculate the pcb impedabce and capacitance of microstrip It appears that you are using AdBlocking software. EM field distribution of stripline and microstrip transmission lines varies. This calculator requires symmetry in the trace widths and location between plane layers. Of course this rule is based on a further approximation, by neglecting T. Wire Pair Capacitance; Wire Over Ground Plane Capacitance; Stripline Capacitance; Rectangular Parallel Plate Capacitance; Microstrip Capacitance; A microstrip width calculator can calculate the width of a microstrip. Such a stripline is constructed with two traces referenced to the same reference planes above and below the traces with a dielectric material between them. 6 pF. Tanδ: Loss tangent of the substrate. Description The inductance calculated using this tool is the inductance of the loop bounded by the flat conductor and the ground planes above and below the conductor. We may use this analogy and the existence of stripline calculators as a means of analysing temperature effects in striplines. Fixed IPC-2152 with modifiers not being selected at program startup after user sets this option. The trace resistance of a microstrip is important in determining how much power it dissipates. This will result in an stripline impedance of about 50 Ω. Calculates the capacitance of biplanar conductors embedded in a homogeneous dielectric medium. Calculations provided on this page are only a small, simplified subset from EMI Analyst models. Coplanar waveguide (CPW) calculator. This calculator is designed to calculate the inductance of a microstrip given its dimensions (width, length and the distance of the strip from the ground plane). PCB thickness. Jan 16, 2022 · This calculator determines the impedance of a symmetric differential stripline pair. w (mm) t (um) Er: h1 (mm) h2 (mm) Impedance: Notes: Apr 6, 2022 · Characteristic capacitance of a stripline: The capacitance per unit length of a stripline is dependent on the dielectric material between the strip conductor and the ground planes as well as the geometry of the strip conductor. Historical Background The need to accurately calculate the impedance of transmission lines, including striplines, has been critical in electronics and telecommunication fields for decades. Mar 1, 1998 · Are there distributed capacitive loads on this trace? See also notes on PCB Impedance and Capacitance Calculator page. Now you try it: 1. Ideal for engineers, designers, and hobbyists working on RF circuits and high-frequency applications. Aug 10, 2023 · Therefore, they require a slight variation of the stripline characteristic impedance. Last but not least comes the definition of the waveguide ports. Mutual Inductance and Capacitance Algorithm Subroutine: mutual_cap_ind(seg,dist1). 0 2. Calculation Notes. εr: Relative permittivity of the substrate. How to Use a Stripline Impedance Calculator Apr 25, 2007 · To improve the VSWR performance of the normal IC-stripline above a metallic can, two novel IC-stripline structures are proposed to measure near-field radiated emissions from on-board metallic cans. Internal Inductance Model Internal inductance of a wire is: Units: Henries Skin Depth is: Units: meters. Code to add this calci to your website Just copy and paste the below code to your webpage where you want to display this calculator. Asymmetric Z o Calculator Capacitance (C): 0. Centered Stripline Impedance Calculator Provide values for three of the four parameters H, T, W, Z o and the relative permittivity of the dielectric. Increasing H increases Zo. Description The inductance calculated using this tool is the inductance of the loop bounded by the two coplanar flat conductors. The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo) and electrical length or vice versa. To summarize, the Stripline Impedance Calculator enables engineers to calculate the characteristic impedance of a stripline based on its geometric dimensions and dielectric properties. com By calculating the stripline impedance, engineers can ensure the proper functioning and performance of these components, enabling effective wireless communication. One of the features of this type of microstrip is the coupling between lines. Microstrip Inductance Model Inductance of the loop bounded by the upper conductor and ground plane is: Units: Henries. Additionally, you can also obtain information such as capacitance, propagation delay, and inductance associated with the stripline using the Stripline Impedance Calculator. From the fundamental definition of capacitance, we have the formula: Calculates the capacitance between parallel plates separated by a homogeneous dielectric medium. Microstrip impedance calculator. The microstrip impedance represents the characteristic impedance of the microstrip line, which is the uniform impedance provided by the uniform cross-sectional dimensions along the microstrip (flat copper conductor) length; to prevent signal reflection. PCB thickness: CapVsT. This calculator below helps calculate the dimension of the mitre bend. 913 pF/cm. A microstrip is created by etching a trace on a printed circuit board and is mostly used in microwave applications. To learn more about the capabilities of EMI Analyst, sign up to access our download area or send us a request. Mar 1, 1998 · calculate the pcb impedabce and capacitance of differential stripline It appears that you are using AdBlocking software. Dec 30, 2023 · With over 300 calculators covering finance, health, science, mathematics, and more, GEG Calculators provides users with accurate and convenient tools for everyday calculations. Based on web pages by Zhi Chang at North Carolina State University . Aug 8, 2024 · This tool is designed to help you determine the inductance of a microstrip line etched on a printed circuit board (PCB). , "Problems in Strip Transmission Lines," IRE Transactions on Microwave Theory and Techniques, Vol MTT-3, No. The characteristic impedance characterizes the impedance existing along the length of the stripline and is relied on for signal integrity, especiall Quickly and accurately calculate Capacitance, Inductance, and Resistance for common conductor configurations. Oct 3, 2024 · This calculator simplifies the complex process of determining the impedance of a stripline based on its dimensions and the substrate's relative permittivity. Another handy guideline for the symmetric stripline in an εr = 4. Here's a bash script that computes capacitance vs. Stripline structures on printed circuit boards (PCBs) are commonly employed to maintain signal integrity in differential pairs. Wire Pair Inductance Model Inductance of the loop bounded by the wire pair is: Units: Henries. Enter the number of plates. This will be some what inaccurate because teh conductors are a significant size wrt to the spacing. Stripline Inductance Model Inductance of the loop bounded by the center conductor and ground planes is: Units: Henries. To improve the computational efficiency we tried wavelets. 25; 3. Note: b is the spacing between two planes and W e is the effective strip width. An asymmetric stripline is constructed between two plane Quickly and accurately calculate Capacitance, Inductance, and Resistance for common conductor configurations. calculate the impedance and capacitance of PCB traces It appears that you are using AdBlocking software. Based on solid engineering principles, EMI Analyst™ leverages transmission line theory, 3-d field solvers, network theory, parasitic elements, linear algebra, proprietary models, and hundreds of formulas developed by the greatest minds in electrical engineering, physics, and computational mathematics. Propagation delay is the amount of time it takes for the head of the signal to travel from the sender to the receiver. It can be calculated using the following formula: Permittivity of striplines: Wire Over Ground Plane Inductance Model Inductance of the loop bounded by the wire and ground plane is: Units: Henries. to NF RELATED LINKS Noise Factor vs Noise Figure Noise Figure vs Noise Temperature Aug 21, 2023 · In modern electronics, differential signaling is widely used for transmitting high-speed data while minimizing noise and signal interference. Odd mode Loss = 0. EEWeb PCB Impedance Calculator: A free online calculator for microstrip, stripline, and coplanar waveguide impedance, based on analytical formulas. PCB Impedance and Capacitance Calculator: Asymmetric Differential Stripline David Campbell Stripline Calculator. Also see: The capacitance calculated using this tool is the capacitance between the wire and the ground plane over the wire length. Mar 4, 2024 · Stripline trace suspended between two GNDs; Trace width (w) = 0. Compute capacitance for the conductor configurations shown below. PCB Structures / Discrete Structures / Signal Management. The plate capacitor was created using two metallic plates and a relative high dielectric (epsilon relative = 12). 2. 5 mm; Trace thickness (t) = 0. 1. Like coaxial cable, Stripline it is non-dispersive, and has no cut-off frequency. Select the dielectric constant. runs scuff-static to compute the capacitance matrix for this thickness Feb 9, 2022 · A stripline impedance calculator can help you determine the width that will be needed to hit a target impedance for a given substrate dielectric and thickness. This assumes other conductors are >10x further away. The Calculator assumes that 1. This calculator is designed to calculate the characteristic impedance of an edge-coupled microstrip. 0740294: Even mode Loss/len = 0. 3. The calculator below uses Wadell’s equations to determine the differential impedance of symmetric striplines, which can be found in the seminal textbook Transmission Line References. Take note that this assumes that the distance between the conductor and the planes is not the same for both reference planes; hence the asymmetric term. Fill in the relative permittivity of the dielectric and the height, width, and thickness of the trace. 035 mm; How to Calculate PCB Trace-to-Plane Capacitance Dec 11, 2024 Dual Stripline Impedance Calculator Provide values for four of the five parameters H, C, T, W, Z o and the relative permittivity of the dielectric. Calculates the capacitance of stripline conductors in a homogeneous dielectric medium. Afterwards the two stripline feedings were modelled. Reference: R. H. com A 90 degree bend in a transmission line adds a small amount of capacitance to the transmission line, which causes a mismatch. Here, the capacitance that makes up C 0 is composed of two components. 1 W/H 3. 36 nH/cm. Stripline Impedance Calculator Calculate Stripline impedance for given PCB parameters. Jul 1, 2019 · Some calculators will allow you to input the equivalent inductance and capacitance per unit length, as well as the conductor’s resistance, substrate conductance, and signal frequency when calculating the impedance of a stripline or microstrip transmission line. , the structure is made up of two dielectric materials: air and the substrate material). com Nov 19, 2010 · What is the capacitance per square inch between the two planes of a two layer FR4 PCB that is . Increasing t decreases Zo, although it has small effect on Zo. 3, July 1955, pp. Some popular options are: Web-Based Calculators. Aug 21, 2023 · Use this user-friendly online calculator to calculate the impedance, capacitance, propagation delay, and inductance of a Microstrip Line on a Printed Circuit Board (PCB). 35; t/h <0. How to use various PCB calculator utilities. Airborne Instruments Labs (Long Island New York, gone but spawned present day companies such as MITEQ) coined the term "stripline", while others such as Sanders (Nashua, NH, now part of The result was called strip transmission line, or Stripline. Provide values for four of the five parameters h, c, t, w, Z 0 and the relative permittivity of the dielectric. The microstrip patch antenna calculator determines the length (L) and width (W) of a rectangular microstrip patch antenna for a given resonant frequency or vice versa. dBm to Watt converter Stripline Impedance calculator Microstrip line impedance Antenna G/T Noise temp. Microstrip Capacitance Model Capacitance between the upper conductor and ground plane is: Units: Farads. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. How much capacitance does a package lead have if it is 0. Atwater, “Simplified Design Equations for Microstrip Line Parameters”, Microwave Journal, pp. A. The capacitance formed by the fringing fields Asymmetric Stripline Impedance Calculator. Wire Pair Capacitance; Wire Over Ground Plane Capacitance; Stripline Capacitance; Rectangular Parallel Plate Capacitance; Microstrip Capacitance; This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. 1 er 15 Note that 1. The website’s user-friendly interface ensures easy navigation and accessibility, making it suitable for people from all walks of life. com asymmetric stripline microstrip calculator to find the impedance of printed circuit boards of a known dielectric constant of material, using javascript language. dual or asymmetric stripline microstrip calculator to find the impedance of printed circuit boards of a known dielectric constant of material, using javascript language. Properly constructed Green&#39;s functions that satisfy With your system, most of the capacitance will be in the field lines around the wires so the result will not be accurate. Mar 1, 1998 · calculate the pcb impedabce and capacitance of dual stripline It appears that you are using AdBlocking software. If the ratio (L/W) is close to unity, the radiation pattern will be symmetric but may not provide a resonable input impedance. Note: valid for (w/h Jan 17, 2014 · For example, a 50 Ohm line 2 inches long has a capacitance of about 6. Calculations provided on this page are a simplified subset from EMI Analyst models. Login Sign up for access | Call : (928) 592-5219 | Email : emianalyst@emisoftware. 40 pF/cm. Please note that signal loss calculations use the dielectric and trace information entered in the impedance calculator. The functions of microstrip and stripline differ in PCB. In the suspended stripline the strip is supported by a membrane. Stripline PCB Impedance is expressed using Ohm. 8 for the relative permittivity of FR4 source(FR4) What is Stripline Impedance? In a stripline, the transmission line configuration is such that there is a flat conductive trace between two ground planes, with a certain dielectric material in between. Oct 21, 2019 · Overview. εeff is the calculated effective dielectric constant of the microstrip line due to the nonhomogeneous nature of the structure (i. An example of the parameterized differential stripline. Broadside Coupled Stripline Impedance. Field Patterns in Cross-Section of Stripline In order to demonstrate the analogy, consider first a primitive parallel plate arrangement. Feb 1, 2021 · The characteristic impedance of the stripline decreases as the strip width W e increases. 0 case is to make B a multiple of W, in the range of 2 to 2. ekyul klqcunx qum agpowa bhhedt ztij njrx cjrratub gcxop ngp