Question: what is the difference between spdt and dpdt?
Answer: The SPDT has two circuits with two choices of “ON.” This also makes SPDT a two-circuit mechanism. On the other hand, DPDT is basically two SPDTs together on the same switch. It is a dual ON-ON kind of switch derived from the characteristics of SPDT. A DPDT switch usually has two (ON-ON) or three (ON-OFF-ON) positions.