The Taylor Valve Tester Model 45D is a general purpose instrument, capable of testing practically every known type of electronic valve except for the larger transmitting types. Any normal fault can be rapidly detected and the general condition of a valve precisely measured by the mutual conductance test. The instrument is self-contained, ac operated and the number of controls have been reduced to a minimum for simplicity of operation. In addition to this Instruction Manual, the instrument is supplied complete with a Taylor Valve Data Manual giving test data for approximately 7,000 valves. In addition, valves for which information is not given in the Taylor Valve Data Manual may be tested using manufacturer's data. Cathode ray tubes can also be tested using a suitable adaptor which is available as an optional accessory.