yldouright said:Coulomb
If the 40W version took 2F of capacitance, I shudder to think...but maybe you just raised the rails and kept the bias the same
kilowattski
Did you look at the page I showed you?
Actually the 2 Farads came about because I had it on hand not because it needed it.
Anthony
I did the calculations by hand and yup that is correct. After looking at your schematic again I realized your filter is choke fed. I never use choke fed filters because they waste alot of energy. In your power supply, the choke will waste about 80 watts of power as heat. If you need to supply 6 amps with 14 volts dropped across the choke the calculation P=V * I results in 84 watts being dissapated in the choke. It's gonna be mighty hot!!! A CLC filter is a much better choice.
kilowattski
Glad you had a chance to look it over. I don't think the CLC would help this case since the inductor is what is causing most of the voltage knockdown but even if he used a CRC layout the diodes doing the full wave rectification would still be sapping 60W!!! Speaking of power supply designs, have you tried "psu designer"? I looked at it and still can't figure out how to read the charts. I see the values on the left side but there is no ripple output reading in the matrix so how does one know how much ripple to expect from a design?
Glad you had a chance to look it over. I don't think the CLC would help this case since the inductor is what is causing most of the voltage knockdown but even if he used a CRC layout the diodes doing the full wave rectification would still be sapping 60W!!! Speaking of power supply designs, have you tried "psu designer"? I looked at it and still can't figure out how to read the charts. I see the values on the left side but there is no ripple output reading in the matrix so how does one know how much ripple to expect from a design?
You know it's funny, I never bothered calculating out my Power supplies. I just bodge it together and just swap out parts and use a variac to get the final voltage I need under load. Then I get the required parts and put it all together.
BTW who here thinks that 2 Farads is way too much capacitance? I have 8 250,000 Uf 25 VDC caps, 2 250VA 12VAC toroids and I was thinking either Dual mono in a single chassis with 1 Farad each or a single power supply with 2 Farad. I have some 1.8 mH Inductors I was going to use with 0.387R across the coil.
Regards
Anthony
BTW who here thinks that 2 Farads is way too much capacitance? I have 8 250,000 Uf 25 VDC caps, 2 250VA 12VAC toroids and I was thinking either Dual mono in a single chassis with 1 Farad each or a single power supply with 2 Farad. I have some 1.8 mH Inductors I was going to use with 0.387R across the coil.
Regards
Anthony
yldouright,
I use PSUD2 all the time. That is what made me see I was a little dyslexic when looking at your post yesterday. If you do the simulation on a CLC you will see that the results are much different than a LC. If a large capacitor feeds your inductor the inductor will see a much smaller component of ripple to react to therefore dropping alot less voltage. Don't forget and inductor has very little resistance to direct current and reacts only to an alternating current. If you do the simulation you will see that. Try it!
I use PSUD2 all the time. That is what made me see I was a little dyslexic when looking at your post yesterday. If you do the simulation on a CLC you will see that the results are much different than a LC. If a large capacitor feeds your inductor the inductor will see a much smaller component of ripple to react to therefore dropping alot less voltage. Don't forget and inductor has very little resistance to direct current and reacts only to an alternating current. If you do the simulation you will see that. Try it!
Look at the voltage across R1 (your load). Scale the graph using the buttons on the right side and you will see ripple. Don't forget the ammount of ripple is affected by the load you choose. If the load increases it will cause the capacitors to discharge faster therefore causing more ripple. That would be a good test for the software to show.
kilowattski
When I zoom in I see what are ripples but how do you conclude the expected voltage amount from the graph? Also, the load resistor is only R(1) in a CLC, LC or RC configuration. In a CRC configuration it is R(2). Is the default 5K value appropriate? What does it represent and how would things change if we used a current source for the load? What would be the approriate values to use if we used a step current load?
When I zoom in I see what are ripples but how do you conclude the expected voltage amount from the graph? Also, the load resistor is only R(1) in a CLC, LC or RC configuration. In a CRC configuration it is R(2). Is the default 5K value appropriate? What does it represent and how would things change if we used a current source for the load? What would be the approriate values to use if we used a step current load?
yldouright,
The "Y" axis is voltage so you can read the ripple's amplitude value just like you would on an oscilloscope. If you are building an Aleph-X 100 you can figure on about 22 VDC and 6 amps. If you use good old ohms law R=V/I you should have a load resistor of about 3.7 ohms. Replace the R2 value with 3.7 and you will simulate the real life load of your power supply. The 5 Kohms resistance is just a default value used by bottleheads (meant in a kind way). Forget the stepped current load as it does not apply here (my opinion).
The "Y" axis is voltage so you can read the ripple's amplitude value just like you would on an oscilloscope. If you are building an Aleph-X 100 you can figure on about 22 VDC and 6 amps. If you use good old ohms law R=V/I you should have a load resistor of about 3.7 ohms. Replace the R2 value with 3.7 and you will simulate the real life load of your power supply. The 5 Kohms resistance is just a default value used by bottleheads (meant in a kind way). Forget the stepped current load as it does not apply here (my opinion).
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.