341 DC Inverter AC Outdoor Unit Circuit Board Course - Repair / Function / Troubleshooting - Part 3

in this video DC Inverter AC Outdoor Unit Circuit Board Course - Repair / Function / Troubleshooting - Part 3 i discussed TNY278 switch mode power supply, it switches at 132 KHz and the high frequency transformer transfers voltages in output 12 volt, 15 volt and a LM7805 voltage regulator regulates 5 volt for microcontroller. 15 volts are used to bias ipm, intelligent power module, and 12 volts are used to apply biasing relays and UL2003 / ULN2003 IC.
in Part 2 • 338 DC Inverter AC Ou...
DC Inverter AC Outdoor Unit Circuit Board Course Repair / Function / Troubleshooting Part 2 i discussed the rectifier circuit, dc rail, bulk capacitor, pfc circuit, IGBT in power factor correction circuit, reactor and metal oxide voltage arrester (MOV) and ceramic capacitor for ripple removal.
To Watch Part 1 of this series • 335 DC Inverter AC Out...
DC Inverter AC Outdoor Unit Circuit Board Course Repair / Function / Troubleshooting - Part 1. in this part i discussed the components in EMI Electromagnetic Induction / RFI Radio frequency interference. it contains fuse for current protection, first stage filter for high frequency harmonics, mov metal oxide varistor for high voltage protection, surge arrester for lightening arrester. then we have PTC for positive temperature co-efficient to protect over current surges. then there is a a bypass relay to operate the circuit in normal mode. in any conditions the microcontroller turns off the bypass relay and the circuit load is transferred to PTC for more protection