Ok, I'm trying to design a power supply to power a standby LED, temp sensing IC, and momentary switch. I was planning on using the circuit presented by kristijan-k here,
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6628
I was going to use a regulated power supply like this one...
http://www.hut.fi/Misc/Electronics/circuits/psu_5v.html
but with a 9V IC.
What I was wondering is what value transformer I need to get in order to get 15V after the bridge rectifier. Is there a formula for calculating the DC voltage after rectification compared to the secondary AC volatages?
Thanks,
Wes
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6628
I was going to use a regulated power supply like this one...
http://www.hut.fi/Misc/Electronics/circuits/psu_5v.html
but with a 9V IC.
What I was wondering is what value transformer I need to get in order to get 15V after the bridge rectifier. Is there a formula for calculating the DC voltage after rectification compared to the secondary AC volatages?
Thanks,
Wes
Richard C said:WIth no load connected to the power supply the peak secondary voltage will appear at the capacitors immediately after the bridge.
V peak = Vrms x 1.414
The final value with load connected depends on the transformer used and the current drawn by the load.
V peak = Vrms x 1.414 - diodes drop (1.6 to 2V for a bridge) - losses.
The diode drop is especially important at low voltages.
sreten.
Right, I know at least 3 V more than the regulated voltage.
But what I was wondering is that would give me +- 15V DC, as in a 30 V differential. Would I just then tie the -15 to ground and use only the + 15, or is there a way I can utilize both the positive and negative terminals off the rectifier to give a + 9V (after a regulator IC) with respect to ground? Or would it just be easier to use only the positive terminal.
I'm used to the PSU on my leach amp which utilizes both the positive and negative voltages. But I think that I only need a +9V to power the momentary switch.
Thanks,
-Wes
But what I was wondering is that would give me +- 15V DC, as in a 30 V differential. Would I just then tie the -15 to ground and use only the + 15, or is there a way I can utilize both the positive and negative terminals off the rectifier to give a + 9V (after a regulator IC) with respect to ground? Or would it just be easier to use only the positive terminal.
I'm used to the PSU on my leach amp which utilizes both the positive and negative voltages. But I think that I only need a +9V to power the momentary switch.
Thanks,
-Wes
bump
sorry, just wanting to get started...
My main questions are
1) Do I just use the output from half of the bridge rectifier and tie the negative DC voltage tab to ground?
2) or is their a way I can invert the negative voltage and then add it in series to the positive voltage?
Either option is good, although I already ordered a tranformer to give me +-15 V and was planning on pursuing option (1). Any input on these questions is appreciated!
Thanks,
Wes
sorry, just wanting to get started...
My main questions are
1) Do I just use the output from half of the bridge rectifier and tie the negative DC voltage tab to ground?
2) or is their a way I can invert the negative voltage and then add it in series to the positive voltage?
Either option is good, although I already ordered a tranformer to give me +-15 V and was planning on pursuing option (1). Any input on these questions is appreciated!
Thanks,
Wes
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