Description

Thornton 3650 10-inch electrical engineering slide rule made in England by A.G. Thornton Ltd under their PIC (Precision Instrument Company) brand. Metal-framed glass cursor. Black cloth covered card case.

It features specialised electrical scales alongside standard mathematical computations. The front scales are cm, LL2, A, B, C1, C, D, LL3, inches, S, L, and T.

An arrow shaped extension on the left end of the slide comprises a domed end including chiselled edge and is known as a mechanical indicator pointer. When the slide is pulled to the right, the pointer aligns with Dynamo/Motor efficiency (%) and Volt conversion scales stamped into the internal well (the exposed inner floor of the frame visible when you pull out the central slide) of the slide rule.