Rapid 4-terminal measurement
The BS407 uses a four terminal measurent system via high quality Kelvin Clip lead(supplied).
For speed and convenience front panel switches are provided for current diversion (allowing in-situ zero adjustment) and current reversal (for identifying thermal emf errors). An LED indicator warns of open circuit leads thus preventing spurious results from being recorded.
Battery operation with built-in charger
The BS407 is a fully portable instrument which operates from NiMh rechargeable batteries. The battery charger is built into the instrument and can be operated continuously during bench use.
Wide measurement range
The BS407 has eight push-button selected decade measurement ranges from 1.999mOhms up to 19.99kOhms.
This unusually wide range makes it suitable for a greater variety of applications than other micro-ohmmeters.
A front panel operated ‘clamp' switch is available to limit the maximum voltage across the unknown to 20mV. This is a requirement for the measurement of switch contact resistances to international standards.
High resolution and accuracy
With a lowest range of 1999µOhms the BS407 can resolve one micro-ohm.
Precision analogue circuitry ensures a high measurement accuracy of up to 0.1% of reading ± 1 digit.