The EL750B is ideal for verification of single output power supply operation.  Static or dynamic resistance loading tests performance such as output lregulatoin or transient response.  External variable load modulation can determine output impedance at specific frequencies.  In the constant current mode, it functions to test discharge rates of batteries or capacitor banks.  Used with a DC power source, it becomes a variable constant current supply useful for measurement of resistance values of components or motor coils under operating conditions.  The forward voltage drop of rectifier diodes or high current terminal connections can also be tested in this fashion.