I got two ways to get 5V from the bridge rectifier connected to 110VAC:
1-By using the LM7805
2-By using Zener diode 1N4744A
My question is which approach is better?
Just the opposite. The voltage out vs load current of an IC regulator is much flatter than a series resistor-shunt zener regulator.
Isn't the 4744 a 15V zener, not a 5V one?
You are right. I meant 4733A.
The reason I am posting this question is because my boss saw this zener circuit and said that zener-resistor based regulators are crude, cheap, and they wont handle situations where the AC voltage drops to 100VAC.
For some reason, I used to think that inside the LM7805 there is a Zener!
Actually I built two circuits, one using the LM7805, and the other using Zener diode 1N4744A. They both work OK, and I am getting 5VDC.
My question is not about how to get 5VDC; I am just wondering if the LM7805 is a better regulator than the Zener diode 1N4733A. I know the Zener is cheaper, and does not require heat sink.