Does the capacitor turn the polarity of the voltage

[philipshadow]

As you can see in the diagram after ac is converted to dc, we have both positive and negative voltages.You can see that the capacitor with the positive polarity is connected to the negative terminal of the diode and the negative lead of the capacitor is also connected to the positive side of the diode(D1 and D2). Therefore the positive voltage from the diode is now converted to a negative voltage which then flows through the resistor and even to the zener diode.
i am with the view that voltage of one polarity can be turned to the opposite polarity by a capacitor just like this diagram. Correct me if i am wrong.

 

[Minder]

The output of the bridge is correct for C2?
Nothing is being reversed, the power supply +ve is referenced to chassis GND.
The zener is 3.8v to 4.2v

 

[Audioguru]

As you can see in the diagram after ac is converted to dc, we have both positive and negative voltages.

Absolutely not! There is no positive voltage since the positive output from the bridge rectifier is at ground (0V).
Then the bridge rectifier output is a negative voltage that is filtered with C2.

 

[philipshadow]

Absolutely not! There is no positive voltage since the positive output from the bridge rectifier is at ground (0V).
Then the bridge rectifier output is a negative voltage that is filtered with C2.

okay. Does it mean that i can only test for voltage at the negative terminals only.

 

[Minder]

If you use the chassis GND for reference, voltages will negative with respect to it.
If you want to use the conventional mode, then use the -ve side of the bridge as the reference.