Weird. I have both simulated (shown in picture) and practical circuit built. Simulation works as expected.

On the practical circuit, the output of the full-wave bridge rectifier gives the result similar to simulation. But after implementing a voltage divider (in order to scale-down the rectifier's output voltage of 7.3V to 4V for microcontroller to read) at the rectifier's output, the output of the voltage divider (as well as the output of the rectifier) gives a value near-zero (millivolts range). Any idea what happen to my practical circuit?enter image description here

(As you can see, the simulated circuit is working as expected, 7.3V can be scaled-down to 4V. But not sure what's the reason of the practical circuit being brought down to approx. 0V after implementing the voltage divider...)

(Transformer: Scales down 230Vrms to 6Vrms; FW Bridge Rectifier: Convert sine AC to pulsating DC; Voltage Divider: Further scale-down voltage to 4V)

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    \$\begingroup\$ In the simulator it is shown that you get what you expect so the circuit is OK. Is your physical circuit exactly the same? Did you double-check? How do you measure the output voltage? \$\endgroup\$ – Bimpelrekkie Sep 14 '20 at 10:21
  • \$\begingroup\$ Is the MCU pin accidentally an output instead of an input? Are the resistor values in your circuit correct and connected properly? \$\endgroup\$ – Justme Sep 14 '20 at 10:22
  • \$\begingroup\$ It all depends what else you have connected to V0_output(1). Look for some low impedance to GND on the board that isn't in your simulation. \$\endgroup\$ – user16324 Sep 14 '20 at 11:37
  • \$\begingroup\$ @Bimpelrekkie Yes I did double-check. I measured the output using: - True RMS multimeter: Red probe on the VD_output, black probe on the other leg of the 10k resistor. - Oscilloscope: Main probe on VD_output, side black mini probe on the other leg of the 10k resistor. \$\endgroup\$ – Shawn Sep 14 '20 at 13:27
  • \$\begingroup\$ @Justme no MCU pin is connected yet. Just testing the transformer, bridge rectifier and the voltage divider alone just like how it is connected in the picture provided. \$\endgroup\$ – Shawn Sep 14 '20 at 13:31

Found out the problem on my practical circuit. CONTINUITY problem.

I've used jumpers and crocodile clips to connect from source to components. Jumper wires are fine. But this is the first time that I've found out there's also continuity problem in crocodile clips as well. After replacing and testing all the wires' continuity, the oscilloscope waveform shown is the same as the waveform shown in the simulation (picture).

Proteus Simulation of the Scaled-down Rectified Output: Proteus Simulation of the scaled-down rectified output

Practical Oscilloscope Waveform of the Scaled-down Rectified Output: Practical output waveform of the scaled-down rectified output via Oscilloscope


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