This is entirely untrue.The zener voltage would need to be 2X the peak AC voltage
This is mudled thinking and is basically untrue.If you use the Zener diode, it will allow the flow of current where it hasn't to flow, i mean if the current is exceeds the Izk when it is reverse biased it will allow it to flow, and then it won't be exactly rectifing.
zener forward voltage + zener reverse voltage > peak AC voltage
The 2V you are talking about is the requirement of an ordinary diode in a power supply to prevent it "zenering," as some power supplies produce an AC voltage that is twice the "expected" voltage due toThe zener voltage would need to be 2X the peak AC voltage.
The zener voltage would need to be 2X the peak AC voltage
This is entirely untrue.
The zener voltage is actually the PIV rating of the diode!!!!!
You can use any diode and the PIV rating of the diode becomes the zener voltage of the bridge above.
I understand what Colin55 said, but now i have a question for you, what about the current that goes through the zener? how much would it be? i think it doesn't matter if it makes it to the load anyway and finally in the load you have the same current as you had a conventional bridge, but would it?
It's wrong. For an 18V zener in the configuration posted, the voltage across the bridge will be 18V + 0.6V = 18.6V. The voltage across the load capacitor will be less than this by 2 diode drops; so what you said (17.3V) is correct (assuming 0.7V diode forward voltage).Why 18.6 V?
Increasing the load (i.e. decreasing the load resistor) will cause the output to droop more. It will be charged throughout the input cycle which will give an oscillating voltage on the load.Why 18.6 V? i simulated it first without the capacitor and i actually obtained the clipped rectified wave, but it was clipped at 13.4V, i used a load of 576 Ohm and the limiter resistor was 10k, then i put the capacitor and it was oscillating and it remains contant, well oscillating between 13V and 13.4V then i changed the load to 10K and it remains constant at exactly 13.5V, and if i change the limiter to 1K, i have again the little oscillation, but it is not at 18.6V it is at 13.4 V,
why? i've already checked, by the way the zener is 1N5248B