Author Topic: Transformer half wave rectifier inbalance in voltage  (Read 1444 times)

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Offline ZeTeXTopic starter

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Transformer half wave rectifier inbalance in voltage
« on: June 18, 2016, 11:23:27 am »
Hi  :)
I have the following schematic on breadboard:

Where V1 is 230/12V 3VA transformer, that outputs 15VAC RMS no load.
C1/C2 are vishay 470uF 50V caps.
D1/D2 are just jellybean diodes

The issue I'm having is that the voltage is not equal on the caps, for the positive cap (C1) I measure about 20V no load and with 240ohm load I measure about 14V, and for the negative cap (C2) I'm measuring about 7.50V no load and with 240ohm load I measure about 6V~.

Why is it so?
 

Online PA0PBZ

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Re: Transformer half wave rectifier inbalance in voltage
« Reply #1 on: June 18, 2016, 11:34:46 am »
Swap the diodes.
Does the problem move?
Yes -> bad diode.
No  -> bad cap.

Keyboard error: Press F1 to continue.
 

Offline ZeTeXTopic starter

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Re: Transformer half wave rectifier inbalance in voltage
« Reply #2 on: June 18, 2016, 11:46:19 am »
Swap the diodes.
Does the problem move?
Yes -> bad diode.
No  -> bad cap.
Fixed! Bad diodes.
thanks!
 

Offline Audioguru

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Re: Transformer half wave rectifier inbalance in voltage
« Reply #3 on: June 18, 2016, 02:49:07 pm »
The extremely high unlimited inrush current blew up the little low power diodes. Why not use rectifier diodes made to do what you are doing? 1N4001.
 

Offline ZeTeXTopic starter

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Re: Transformer half wave rectifier inbalance in voltage
« Reply #4 on: June 18, 2016, 03:42:20 pm »
The extremely high unlimited inrush current blew up the little low power diodes. Why not use rectifier diodes made to do what you are doing? 1N4001.
I'm using 1N4007 anyways, I might have shorted out something that killed the diodes, but it fixed now anyways.
 


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