Osborne High Frequency Current Transformers operate at frequencies higher than 50/60 Hertz. Their purpose is to reduce high frequency system currents to lower values that are appropriate for instrumentation and/or protection circuits. They have been designed to meet specified current ratios, and burden impedance at a specified transformation error. One area of unique Osborne expertise is in designing for phase shift when high frequency current transformers are to be used for power measuring applications.