BS407 WideRangeLowResistanceMeasuringInstrumentBS407-PrecisionMicroOhmmeter Highbasicaccuracyof0.1% Widerangeof1?Ohmto20kOhm Currentreversalswitchfordetectingthermalemfeffects Currentdiversionswitchforeasyzero-ing FourterminalmeasurementusingKelvinclipleads Batteryoperationwithbuilt-incharger 20mVclampfor慸rycircuit?testing