What makes FiderisTM loads special to fuel cell testing?
The FETs are placed in parallel so that their total ‘on’ resistance is about 4% of the resistance of any single element and the power being dissipated is distributed evenly among the FETs. Most loads are specified according to the amount of power that load can dissipate and the number of FETs in the load is determined by the total power being dissipated by each FET. As an example, common FETs can easily dissipate several hundred watts of power, so even two FETs would be suitable for a 1,000 Watt load. However, each FET has a minimum resistance and the minimum resistance of this hypothetical two-FET 1 kW load would be that of the two resistors (FETs) in parallel which may be about 10 milliohms. Therefore, if a user were testing a large single cell with a full current of 1000 amps, the smallest voltage drop across the load (i.e., full on) would be 10 Volts! Clearly not acceptable for single cell testing. FiderisTM electronic loads are designed not only by maximum power but by minimum res
