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Voltage regulator output question

BRO

Oct 21, 2013
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Oct 21, 2013
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Hi all, fair to say I am new to circuit building, but have been slowly getting some experience.
The question I have is regarding Voltage regs. I am rectifying 26Vac with a 2A bridge rectifier. I get about 23Vdc output. I then connect my 7815CV voltage regulator to the DC output, but I am only seeing 12VDC. I am not sure why, can anyone shed some light on it?
Thanks
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
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Hello and welcome to Electronics Point :)

Start by showing us a complete circuit diagram.

Do you have a smoothing capacitor after the bridge rectifier? Your answer should be yes.
 

Harald Kapp

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Nov 17, 2011
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Do you have a smoothing capacitor after the bridge rectifier? Your answer should be yes.
I guess the answer will be no. That explains the 23V DC measured and the irregular behaviour of the 7815.

Also a pair of decoupling capacitors (100nF each) from input to GND and from output to GND will help the 7815 to work stable.
 
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