Power supply issue
#31 Re: Power supply issue
No.
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#32 Re: Power supply issue
Thank you .
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#33 Re: Power supply issue
No. The positive and negative terminals are the DC outputs of the rectifier. They should not be connected to the transformer.
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#34 Re: Power supply issue
Nick got there first....
The world looks so different after learning science. For example, trees are made of air, primarily. When they are burned, they go back to air, and in their flaming heat is released the flaming heat of the Sun which was bound in to convert air into tree.
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#35 Re: Power supply issue
You do now.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#36 Re: Power supply issue
Ignoring the snark, it may be worth spending 5 minutes looking how a bridge rectifier is constructed fro 4 diodes and if I tell you that a diode will only pass current if the anode is at a higher voltage than its cathode (for conventional current, ignore than DQ, that's to quiet the others down). First think about how and when the sine wave from the transformer in this circuit will pass current into the capacitor, and then do the same for the case of the bridge rectifier, and consider why the first is a half wave rectifier and the second a full wave rectifier.
In this diagram, its important to remember the two ground symbols (the downward pointing triangles) are connected together, you need to know that to see how the current flows back through the bridge.
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#37 Re: Power supply issue
I thought rectifiers just turned ac into dc . So 18v ac became 18v dc
That as always been the case , but these new ones are driving me mad.
I’m getting 18v ac and 9v dc ( this is without any capacitors) What is going on?
I’ve tried another transformer 35v ac 17v dc it seems to be halving it ?
That as always been the case , but these new ones are driving me mad.
I’m getting 18v ac and 9v dc ( this is without any capacitors) What is going on?
I’ve tried another transformer 35v ac 17v dc it seems to be halving it ?
#38 Re: Power supply issue
That has never been the case. And I remember telling you that just after you joined this forum.I thought rectifiers just turned ac into dc . So 18v ac became 18v dc
That as always been the case , but these new ones are driving me mad.
Well, if you spent the time I suggested you may have had the answer. How are you measuring the DC? Without the cap you will have a rectified sine wave, that will have an average DC level and a peak DC level. No idea what your measuring device is showing you.I’m getting 18v ac and 9v dc ( this is without any capacitors) What is going on?
No idea. a rectified and filtered supply (with a cap) will give you 1.414 times the AC voltage as an off load voltage and depending on the load anything from that down to 0v output.I’ve tried another transformer 35v ac 17v dc it seems to be halving it ?
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#39 Re: Power supply issue
If you have told me I apologise for paying insufficient attention .
Nothing is as simple as it seems and this hobby was supposed to be light relief as I recovered .
So the only law is the dc output after capacitors is 1.4 the ac input ?
Nothing is as simple as it seems and this hobby was supposed to be light relief as I recovered .
So the only law is the dc output after capacitors is 1.4 the ac input ?
#40 Re: Power supply issue
No, no law's involved (either sorts), just maths. The peak value of a sine wave is 1.414 (square root of 2) times its RMS (the equivalent power value of a DC voltage) value. With no load, the capacitor after the rectifier will be charged up to the peak of the sine wave, So the peak voltage is 1.414 times the RMS AC voltage. As the load on the charged capacitor increases the average voltage on the capacitor reduces, if the load is 0 ohm, the voltage will be 0v.
https://www.audio-talk.co.uk/phpBB3/vie ... 15#p191815
https://www.audio-talk.co.uk/phpBB3/vie ... 15#p191815
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#41 Re: Power supply issue
Not sure what snark is, but I was alluding to the fact that Dennis (DQ) did not seem to understand bridge rectifiers. There is so much to learn.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#42 Re: Power supply issue
He never said he did, what he said was that he knew how to wire them. Which may or may not have been true. To understand something is a far wider goal that just knowing how to use it, and is a journey that none of us ever probably reach the end of. My suggestion of following the paths the current takes in the two example I gave, and the corresponding voltages generated will IMHO take you along the first part of understanding and help to explain why you use them as you do. And also as it happens will help in understanding the next answer I gave about the value of the DC voltage generated.but I was alluding to the fact that Dennis (DQ) did not seem to understand bridge rectifiers
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#43 Re: Power supply issue
More power to your elbow Nick, you (and others here) have certainly helped me enough over the years.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)