Circular slide rule, 'Robinson Calculator', aluminium / plastic, designed by R B Robinson, made by A W A Australasia, Australia, 1957-1962
A circular slide rule, with an aluminium base and handle. There is one aluminium slide and three clear plastic slides marked 'REAL' and 'IMAG' and one thicker perspex top layer.There are two aluminium studs on the uppermost plastic scale. There is blue and red graduated scales on the aluminium base.
'ROBINSON CALCULATOR' printed on the upper perspex layer, and 'MADE BY AMALGAMATED WIRELESS (AUSTRALASIA) LTD FOR THE ELECTRICAL RESEARCH BOARD.