R1902 Inductor

This 20 microhenry inductor was dropped on the floor by its then owner, back in 1980 something. It was subsequently rebuilt using a clear perspex cover, so the winding is clearly visible. The three cross-bar supports were also broken and were replaced by PTFE versions.

The right hand picture shows the added single-turn "calibration" winding that was used for fine adjustment of the calibrated inductance value.