From his original diagram it looked like Vgs was 0V ie nothing connected to gate other than multimeter.
Last edited:
No need to explain. You're initial drawing wasn't clearly labelled and my brain was only partially functioning (as usual)
Hi Pico,
I have looked for the new thread but haven't found it. Could you point me to it?
Thanks,
Albert
Hi,
I am too intending to build Aleph 30. I will need some help from you experts. what is the meaning of I-FET and PWR in circuit diagram "Adj bias current". does it meaning each Mosfet power consumption in amp and watts?
Thanks.
I am too intending to build Aleph 30. I will need some help from you experts. what is the meaning of I-FET and PWR in circuit diagram "Adj bias current". does it meaning each Mosfet power consumption in amp and watts?
Thanks.
Yes. I-Fet is an electrical way of saying current in amps per fet. PWR is expressed as usual in Watts.. which equals the resulting Pd (power dissipation) in watts. Generally speaking, large signal fets such as the sort in question are capable of dissipating a certain number of watts, which in turn is dependent on your ability to cool them. ie, how much heatsinking are you using? If that answer is "i have adequate heatsinking" capable of say.. 120 watts at a 25deg C rise. Then you are capable of running those Fets at 30 watts a piece, and whatever current (I) that is proportional to that Pd, at a given voltage of the power supply you are using.
Thanks. I have Transformer that is 43-0-43 10a so I wanted to step down to 20v with regulator but today I had soldered wire from its secondary coil and made 20.6-0-22.6v ac
do you think it will be problem with this difference voltage?
do you think it will be problem with this difference voltage?
I think I am near to solved the problem from Power supply forum. It can use rail splitter circuit so the voltage can be around 21.5vac. hope can manage it properly. Thanks
Hi,
I bought a toroidal transformer (600VA 20-0-20 V) and now I'm doing the part list to order on digikey.
Now, I'have a question about the resistors on the Power supply board.
I use the BrianGT boards. For the Power Supply, BrianGT give the part list and, for the resistors, at the position R3-R12 there is a description that says to use a short circuit jumper and a note says "for the standard CRC configuration, no R is needed".
Shall I let the position R3-R12 empty? Or must I use a piece of conductor to do a short circuit?
Thank you
I bought a toroidal transformer (600VA 20-0-20 V) and now I'm doing the part list to order on digikey.
Now, I'have a question about the resistors on the Power supply board.
I use the BrianGT boards. For the Power Supply, BrianGT give the part list and, for the resistors, at the position R3-R12 there is a description that says to use a short circuit jumper and a note says "for the standard CRC configuration, no R is needed".
Shall I let the position R3-R12 empty? Or must I use a piece of conductor to do a short circuit?
Thank you
I used the same board and used the jumper wires without a problem. I would build as suggested for starters.
I find that note in the BrianGT BOM confusing. Aren't those resistors the "R"
in the CRC configuration? With jumpers you get a straight capacitor supply
(not that there's anything wrong with it.)
Dennis
I actually replaced all my jumpers with .47 resistors at a later date. I did not notice any difference actually. I am like you and did not like the board or the fast diodes. I removed the capacitors at a later time and just wired my PS point to point using bridge rectifiers. There is not much to wiring a PS PP and I see no need for a board. I just thought to keep it simple for a first time builder and just said to build as described. It does work.
Question about matching mosfets:
during matching process the mosfet became hot?
Or does it be still cold?
during matching process the mosfet became hot?
Or does it be still cold?
I do not remember mine getting hot but if you are sure you have the testing circuit right I would not worry about it. I do not remember leaving mine hooked up long enough to get too hot.
Hot or cold .depend on current flow of mosfet. Should matching it together to make sure it is the same Vgs , same temp.....
Whitout heatsink, power mosfets IRFP240 became very hot in a few time!
Whit heatsink they are cold!
Whit heatsink they are cold!
Finally I matched all IRFP240.
Now I'm matching IRF9610.
Which is the Vgf expected for this mosfet? The current is about 10mA...
Thank you!
Now I'm matching IRF9610.
Which is the Vgf expected for this mosfet? The current is about 10mA...
Thank you!