Post Office Box – Plug Type

Description

The 3-Ratio P.O. Box has sixteen non-inductively would coils 1, 2, 2, 5, 10, 20, 20, 50, 100, 200, 200, 500, 1000, 2000, 2000, 5000 ohms and two proportional arms each with coils of 10, 100, 1000, ohms.

Two spring keys having good contact for battery and galvanometer is also provided.

Accuracy of constantan coils 0.1% for lower values and 0.5% for higher values. The whole system is contained in a superior quality wood box.