Protective arrangement for dependent switching circuits

Abstract From the Canadian patent

This invention comprises a fusible resistor in a solid astate relay comprising two solid state switches connected in parallel with each other, but in series with a load and a source of current. When the first of the two switches is switched on, the second switch also switches on and con-, ducts, supplying sufficient current to the load thus reduc-, ing the voltage across both switches to that of the voltage drop across the second switch. Should the second switch fall to become turned on When the first switch is turned on there will be a higher voltage across the first switch (and the components in series with it, if any) causing excessive current to flow through the first switch resulting …