Active calculator for microstrip transmission line using a formula quoted by Rick Hartley giving characteristic impedance and effective dielectric constant, with equations usDJ Circuits was established in 1968 and is one of the UK’s oldest, independent, manufacturers of Printed Circuit Boards. Based in Harrogate, North Yorkshire, DJ manufactures and supplies PCB’s to a wide and varied range of customers and our commitment to supplying the highest quality products, on time, at competitive prices is paramou