varistor, inductors, capacitor and relay on green circuit board

background beautiful black blue board capacitor choke circle circuit closeup coil colored component copper copy core cylinder design detail development device disassembled dismantled electric electrical electromagnetic electronic electronics electrotechnical electrotechnology engineering ferrite green inductance inductor industrial industry inverter laboratory macro magnetic network nobody nopeople orange part pcb power protector reflection relay repair research resistance resistor round science shiny soldered space spare store supply surge technical technology tin transformer twisted unit varistor voltage white winding wire yellow