100watts in 12v dc single rail means power supply must be 8.33 ampere. what about 12v dual power supply? does this power supply also needs 8.33 ampere. its been in my mind for a long time. Anyone know about this?
Dany
Edited by - Ashirdaniel on Oct 05 2016 12:59:23 PM
12V x 8.33A= 100W. If you have two of them then the power is obviously 200W. Are you talking about a dual polarity power supply that produces +12V at 8.33A and -12V at 8.33A?
Are you talking about a 100W audio amplifier? Then the power supply must provide much more than 100W, maybe 180W because of heating. If a 100W audio amplifier has a 12V power supply then its output is about 8V peak-to-peak which is 2.83V RMS. For 100W the speaker impedance must be 0.08 ohms. If the speaker is 8 ohms then its power is only 1.0W.
For 100W into 8 ohms the voltage across the speaker is 28.3V RMS which is 80V peak-to-peak and the power supply must be about +88V or +44V and -44V.
Ys I'm talking about a dual polarity circuit which gives 12v and -12v. It uses 12-0-12 transformer , four diodes in half bridge configuration ( two diodes for ve and another 2 for -ve part) and capacitors to reduce ripple. I mentioned this power supply and audio amplifier as an example. my real system is a 200watts rms sterio(100w 100w) mosfet amplifier and a dual power supply ( uses 27-0-27 transformer and 4 diodes in above mentioned configuration and gives 34v 0 -34v output. Transformer is just 5A and uses two 10000uf 50v electrolytic capacitor each for positive part and negative part) . I made this for my friend. It cost me ₹4000. (60 dollar 💵 ) it also has mic input. I was in real doubt whether it can produce 200watts Rms or not . I saw another amplifier using same amplifier board (200w) and using big 10Ampere 27 0 27 transformer .
Watts to ampere single rail vs dual
Posted - Oct 05 2016 : 12:58:25 PM
