Multimeter 1CO4

The Devry Technical Institute multimeter is essentially the follow-on to the Deforest's Training multimeter using a different meter movement, Beede Electrical number 15, whereas the earlier DeForest's version uses a Simpson type 85.  Sensitivity is 1000 ohms/ volt DC.  The low resistance scale of 0-200 ohms is actually a scale that moves the pointer to full scale for infinite ohms.  The external test resistance then acts as a shunt to reduce the meter reading resulting a a more accurate reading at the lower half of the scale (below 5 ohms).  The high resistance scale works in normal fashion 0-600,000 Ohms.  Other scales include 10-100-500-1000 Volts DC,  10-100-1000 Volts AC, and current 1-10-100 mA DC.  These meters were apparently built by the students as part of their lessons.

The meters can be seen in ads for the correspondence school as it morphed from Deforest's Training to Devry Technical Institute.

In questo link sono elencati 8 modelli, di cui 7 con immagini e 1 con schemi.
Elenco delle radio e altri apparecchi della DeVry Technical Institute; Chicago