The evolution of the ENDECO, Inc. Tethered Current Meter

This paper discusses the invention and evolution of the ENDECO^®Tethered Current Meter from the Type 105 Film Recording Tethered Current Meter through the Type 174 Digital Recording Tethered Current Meter and its present day configuration, the Type 174 Solid State Memory Tethered Current Meter. A brief history describes why the tethered concept was developed and how the data gathering technique was updated for each instrument as technologies became available. Three intercomparison tests are discussed. The development of the Solid State Memory Type 1069 Data Logger and its inclusion into the Type 174 Tethered Current Meter for intelligent control and data storage is discussed. Finally the Type 174 SSM Tethered Current Meter is discussed.