Is it OK to use a zener diode without a series resistor in a transformer-less power supply?

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Michael George

Joined Feb 8, 2015
53
In many circuits, I found that a resistor should be connected in series with zener diode to protect it.
In this circuit, If a series resistor is used, The voltage of the load would NOT be the voltage on the zener diode. The load voltage would be the rectified voltage (230 * 1.414 = 325.22 V DC ). So, We have to use zener diode without the series resistor. But what about the protection of zener diode? The voltage across it is - 325.22 V DC. Is that ok?
Would you give me part number of a zener diode that is suitable for this circuit?
Thank you,

http://www.homemade-circuits.com/2011/12/how-to-calculate-and-deduce-current-and.html
 

BobTPH

Joined Jun 5, 2013
3,800
In this case, the capacitor, C1 is acting in place of the series resistor you would normally find in a DC based zener regulator.

Bob
 

WBahn

Joined Mar 31, 2012
26,398
As noted, discussion of transformerless power supplies is against the User Agreement, therefore this thread has been closed.
 
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