PW4 Resistance Bridge

This unusual Wheatstone bridge is battery operated, using 3 AA cells. The null indicator is concentric with the balance dial, thus providing a very compact unit. The balance dial itself is of the slidewire design giving continuous coverage of each of the six switched ranges.

The instrument covers the resistance range 0.08 ohm to 120 kilohm.

What appears to be a separate carrying case is, in fact, an integral part of the instrument. Three fixing screws underneath have to be removed in order to release the unit from this case so that the batteries can be changed.