Roller-Smith Bridge Ohmmeter

Roller-Smith bridge ohmmeter

Roller-Smith bridge ohmmeter

There is nothing digital about a vintage Roller-Smith bridge ohmmeter.  It can measure from 0.5 ohms to 50,000 ohms using 4 ranges.  This is a beautiful antique test instrument.  It has an attractive hardwood case, leather handle, and quality construction.  

The meter operates on 3 vdc, which can be supplied using two D-cell batteries or a portable external dc  power supply connected directly to the battery terminals.

Usage is very simple.  Connect the resistance to be tested to the terminal posts, select the appropriate range via plug socket connection, push the Test button and rotate dial until meter nulls at zero.  At this point, the bridge is balanced, and ohms is read by multiplying the dial scale reading by the plug-socket range.

Bridge-type equipment has always been very accurate, and this is no exception.

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