| Description |
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A PIC microcontroller (IC2) is in charge. An XBee (IC3) supplies the radio link. IC1 is a 3.3-V supply, which the XBee requires; the PIC uses it as well so no level-shifting is needed for serial communications. The SSRs contain built-in snubbers and load resistors, which is good, but the load resistors assume 5V input, hence the additional regulator IC4 and Q1-2 to do the level shifting. The components coming off of SEC2 are the zero-crossing detect input to the PIC for phase control (not yet implemented in the firmware). |
