Maker's Name: 
University Graham Inst. Co.
Where made: 
11 × 8.8 × 17.5 cm

This current transformer measures the AC current flowing in a circuit, in the range 2.5 milliAmps to 10 Amps. It uses a tapped transformer, with the primary winding in series with the circuit being tested. The unit uses an external 1 mA AC meter, which must be connected to the unit before it is used. Failure to do so may cause a high voltage flashover in the transformer when the test button is depressed.