JimPerry
Senior Member
The Zener is to clamp the Maximum voltage getting to the regulator to a safe, and constant, level - if regulator is rated at 35V max then a 30V Zener will enure that the regulator doesn't get fried.
I think your diagram was wrong - the Zener goes from positive to ground and the ordinary diode goes before it in the positive line - just to prevent reverse polarity connection blowing evrything up! Plus it was probably a 15V Zener (or higher) not 5V.
Ripple is from poorly regulated supplies (residual changes in voltage from the original AC) You want a voltage that is constant (like a calm mill pond) ripple is like waves when the voltage is disturbed -- mixing a few metaphors here!) Capacitors can smooth the voltage ripple down to an acceptable level.
I think your diagram was wrong - the Zener goes from positive to ground and the ordinary diode goes before it in the positive line - just to prevent reverse polarity connection blowing evrything up! Plus it was probably a 15V Zener (or higher) not 5V.
Ripple is from poorly regulated supplies (residual changes in voltage from the original AC) You want a voltage that is constant (like a calm mill pond) ripple is like waves when the voltage is disturbed -- mixing a few metaphors here!) Capacitors can smooth the voltage ripple down to an acceptable level.