Teardown of the Keithley 515A Megohm Wheatstone bridge, plus a tutorial on how Wheatsone bridges work and their applications. Manual & Schematic: https://download.tek.com/manual/515A(Model515A).pdf 1960’s Daven precision resistor and attenuator catalog: http://www.technicalaudio.com/pdf/Daven/Daven_attenuator_switch_lab_Catalog.pdf 00:00 Keithley 515A Megohm Wheatstone bridge 03:50 – The Magic smoke test 04:00 – Zero check test 04:40 – Standardise calibration step 05:30 – ...