The datasheet said 20 volts for vgs. It can dissipate 200 watts, with proper heat sinking. 200W/5A=40V, so 200 watts should be more than enough for a twenty volt supply at 5 amps?
I think I will just limit my load to two amps. I should have far less problems that way. I also calculated the load resistance of my battery pack and it will limit current to 30 amps.
Situation averted. If I do not let the charge voltage-capacitor voltage exceed .125 volts, the cap's resistance would limit the current to ten amps or so. I will just need a relay to charge it through a resistor in the first place, And I'll add some overcurrent circuitry for safety.
I ran some simulations and at only 1 khz with a 5 amp load and my monster cap I found no notable ripple. I will probably switch it just above audible frequency. I have one problem though, The resistor I use to limit the current to charge the capacitor forms a voltage divider with the load resistance, making tha capacitor not able to charge past 10v with a 15v input. Also, is it a bad idea to draw 10A surges from a bunch of AA batteris in series?
I found a capacitor that would be better, 50v, 33,000uF, rated at 17 amps continuous current with 12.5 millohms. I am also not too concerned with ripple, I just care that the minimum voltage is kept to a maximum, if that makes any sense. I plan on feeding the output through an adjustable linear regulator.
I will have two of them switched alternately. The idea is to make two outputs isolated from each other, bot necessarily from the input.I am putting the two isolated outputs in series for a positive and negative supply. I can build an oscillator straight off of the input with enough delay to account for the turn off times being longer than the turn on times. What value inductor and capacitor should I use? And what do I need pwm for?
Very coarse indeed. I plan on using an IRF3205 for the transistors. Two of these circuits will be attached to the same supply and the transistors will be switched alternately. The two capacitors will be connected in series for a positive and negative supply voltage.
i got .5 ohms when I should have seen a little over 1 ohm for the capacitor's resistance. That was a miserable failure due to not having any way to calibrate my 555 circuit, my meter not being accurate enough, and not having a proper ac supply/ resistor.
I think I have found a way to calculate esr. I will use a 555 oscillator and a resistor that will make the time high of the oscillator equivilant to the capacitance. I will plug that into an online calculator to find the reactance of the cap at 60hz. i will put the cap in series with a .1ohm shunt to measure current. I will then measure the voltage across the cap, and the current going through it, and I can calculate additional resistance that way. About what resistance should I expect?
I plan on using large, rather old capacitors. If I have 50% duty cycle, it would charge at 10 amps, right? Is this too much for a standard cap? They are rated at 40v and were pulled from very old switching power supplies.
I have very little money, and actual wire wrap boards are expensive. I only use sockets for ICs, I just poke other components directly through the board, and often the leads are thin enough to wire wrap directly to a socket pin. I sometimes have "hybrid" wire wrapped and point to point soldered boards. I'm cheap. Often I just put caps between the chip and socket and put the cap leads in the same socket hole as the chips power lines.
