It is a transformerless power supply with low resistance protector to protect the voltage regulator transistors. The left source is 100v. The right source is 250v.
TWO WAY SWITCH-POWER SUPPLY VOLTAGE SELECTOR
LEFT ONE WAY SWITCH-SET("ON" THEN "OFF")
RIGHT ONE WAY SWITCH-50 OHM SHORTED(RESET)
BLUE LED-OUTPUT "ON"/"OFF"
