AC to DC Converter (with Full-wave Rectifier) Circuit Design

How does a AC to DC Converter work with full wave rectification and what is the value or Formula for the resulting DC voltage at the output of the AC adaptor circuit? These questions are discussed and answered in this AC-DC converter circuit design and analysis video. This circuit is implemented with two operational amplifiers (Op Amps), two diodes and a few passive circuit components including resistors and capacitors. Both Op Amps should be properly biased with supply voltages applied. The output of each op amp is connected through the circuit to Op Amp's inverting or negative input terminal to enforce negative feedback that keeps op amp in linear region of operation. It is intuitively explained why and how the combination of two Op Amp stages implements full-wave rectifier. In the presented analysis and explanation in the video, it is shown which Diode is turned On and which one is turned off during half periods of the applied input sinusoidal AC voltage. Then the resulting injected AC current is followed to show that the AC current is half wave rectified resulting in positive output voltage. The second stage is effectively realizing a low-pass filter (LPF) with very low cutoff 3dB frequency of 0.8/beta where beta is the scaling value of the feedback resistor for second Op Amp. This very low 3dB frequency of the overall LPF transfer function results in the removal of all non-DC harmonics of the full-wave rectified sinusoid. Therefore only DC component with value of (2*beta/Pi) * amplitude of input sinusoid appears at the output of the circuit.

[VINICIUSBH]

Dear professor thank you for sharing so much information. Best regards from Brazil

[Chupacabras]

Very nice explanation. I would like to see more stuff about poles and zeroes. Especially for compensation of some opamp circuits to prevent instability.

[Guishan_Lingyou]

Very interesting circuit, and explained in a way that even I could understand (I think). Is the practical application of this circuit (as compared to just using 4 diodes and a some filter caps) basically cases where you might want to vary beta, and where you don't need much current at the output?

[emmasteph]

Very educative.... Am a physicist.... Please can you recommend a textbook that can teach me every basic calculation involved in building rectification circuit?...

Thanks ....

[Random-ezkv]

can you make a simulation for this?ive been trying to replicate it but it wont work