EEVblog 1476 - Keithley 515A Wheatstone Bridge TEARDOWN & TUTORIAL

Teardown of the Keithley 515A Megohm Wheatstone bridge, plus a tutorial on how Wheatsone bridges work and their applications. Manual & Schematic: (Model515A).pdf 1960’s Daven precision resistor and attenuator catalog: Keithley electrometer teardown: 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 - Range calibration 06:21 - Measuring a 200M resistor 09:41 - Confirmation with a Keithley DMM7510 7 1/2 digit multimeter 10:37 - Weatstrong Bridge Tutorial 14:55 - Gaurd traces for high impedance measurement 16:22 - Teardown 28:25 - OUCH! Forum: Support the EEVblog on: Patreon: Odysee: @eevblog:7 Web Site: EEVblog2: EEVdiscover: AliExpress Affiliate: Buy anything through that link and Dave gets a commission at no cost to you. Donate With Bitcoin & Other Crypto Currencies! T-Shirts: #ElectronicsCreators #Teardown #Keithley