Howdy again. I liked your way to reduce the complexity of the circuit into two clear branches. My understanding took a huge leap forwards. Regards again.
And again Howdy. I did some experimenting. With values of the coupling capacitor and the choke tuning to series resonance I observed a 90 degrees phase shift over the choke. So I believe the term RF choke is misleading. I would call it an inductor. I used 47 pF and 3,9 uH in series. I fed the circuit 10,7 MHz with my signal generator. I observed phase shifting increase and decrease when changing the frequency. And again Regards.
Howdy. Good except for one thing. Assuming zero deviation. I don't understand the +-90 degrees shifting. Does the choke generate the phase shift ? Or does the coupling capacitor generate the phase shifting ? I understand the choke voltage is 90 degrees advanced to its current. Yes. But to achieve that the current through the coupling capacitor must be small. The capacitor reactance must be high which means the capacitance must be small. Regards.
Answer: When a voltage is applied to the primary of the transformer, a voltage is induced in the secondary, which causes current to flow in the secondary tank circuit. When the incoming signal frequency is equal to resonant frequency of the tank circuit, the tank is at resonance and acts resistive (Xc=XL) Current and voltage are in phase in a resistive circuit. The current flowing in the secondary of the tank causes voltage drop across each half of balanced secondary windings of the transformer. Because the windings are inductive, the voltage across it is 90 degree out of phase with the current through it. The centre tapped arrangement at the secondary causes the voltages at each end of the secondary to be 180 degree out of phase. Please comment for further doubts - Dr. Deepa Elizabeth George
Can't thank you enough Madam. I looked everywhere but there was no reason given for this phase shift. Finally, your explanation did it for me. Thanks a ton!!
@@TocHKochi Ma'am, Thank you again for your reply. Upon analysing your comment I have the following doubts: 1. If the circuit was to consist of simple secondary i.e. no centre tap, and a single resistive load only, then according to the above explanation of winding being inductive, we shall expect the same 90° phase shift between the winding voltage & current. But this doesn't happen because with resistive loads there is no phase shift as such. So my question is, Doesn't the phase shift between volt and current in secondary depend on the type of load connected rather than on the inductive nature of the winding? 2. Regarding the phasor diagram, we know that transformer primary voltage is 180° out of phase with secondary voltage and not the secondary winding current. Thus, even if 90° phase difference exists between the above discussed quantities, it doesn't lead to the conclusion that primary and secondary voltage have 90° phase difference because primary voltage is referenced in phase to secondary voltage and not secondary current.
