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I am using below circuit for PFC. Before connecting coupled inductor's auxiliary output to the IC's Vcc, I wanted to make sure that it is coming properly or not.

So when I probed the red dot in the circuit below, it is showing 0V, doubtfully when I probed blue dot in the circuit below, Instead of pulsating DC at the point, I am observing a 312VDC, straight line. I am suspecting that may be the reason the inductor is not giving any voltage to it's auxiliary winding because there is no change in current at the primary winding. (The measurement of the voltage is done in oscilloscope).

enter image description here

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    \$\begingroup\$ If there is no or very little current taken from the capacitor, it is perfectly normal that the 'blue' dot is a 'straight line'. What is your load? \$\endgroup\$ – Oldfart Sep 5 at 10:52
  • \$\begingroup\$ I have not connected any load \$\endgroup\$ – Voldemort Sep 5 at 11:47
  • \$\begingroup\$ No load might explain why the unit is not switching (The C6 is fully charged and nothing is taken out) which again would explain your 0 V on the red dot. I suggest you put a simple load resistor on the output and then start measuring again. \$\endgroup\$ – Oldfart Sep 5 at 11:54
  • \$\begingroup\$ I have connected 400W electric bulb as load. But the red dot is still 0V, but at blue dot the voltage is rectified full wave. \$\endgroup\$ – Voldemort Sep 5 at 11:56
  • \$\begingroup\$ I have not connected the IC to the any part of the circuit. I wanted to make sure that the auxiliary winding is giving proper voltage or not. So I have disconnected all the connections of IC with the auxiliary winding. \$\endgroup\$ – Voldemort Sep 5 at 11:58

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