I am building a Aleph 5 amp. I purchased 16 IRFP240 mosfets in hope of getting 4 matched up groups of three.
My readings for the Vgs are as follows:
1. 3.68 9. 3.84
2. 3.70 10. 3.85
3. 3.74 11. 3.90
4. 3.80 12. 4.13
5. 3.81 13. 4.21
6. 3.83 14. 4.26
7. 3.83 15. 4.27
8. 3.83 16. 4.27
If I group them as follows :
group A 1-2-3
3.68
3.70
3.74
group B 4-5-6
3.80
3.81
3.83
group C 7-8-9
3.83
3.83
3.84
group D 14-15-16
4.26
4.27
4.27
Should the mosfets be matched up in groups of 3, 6 or 12. ?
Assuming groups of three :
Is it ok to have group D as described or should I buy more mosfets to get even better matching.
I used a 24 volt supply and a 30 ohm 30w resistor to get these readings. No heat sinks and took reading after 6 minutes.
I bought 10 9610's and was able to get a group of four at 4.1 Vgs.
I used a 24 volt supply and 2k resistor. Reading stabilized after 2 minutes.
The 240's did get quite hot but the 9610's hardly warmed up at all. Is this normal?
My readings for the Vgs are as follows:
1. 3.68 9. 3.84
2. 3.70 10. 3.85
3. 3.74 11. 3.90
4. 3.80 12. 4.13
5. 3.81 13. 4.21
6. 3.83 14. 4.26
7. 3.83 15. 4.27
8. 3.83 16. 4.27
If I group them as follows :
group A 1-2-3
3.68
3.70
3.74
group B 4-5-6
3.80
3.81
3.83
group C 7-8-9
3.83
3.83
3.84
group D 14-15-16
4.26
4.27
4.27
Should the mosfets be matched up in groups of 3, 6 or 12. ?
Assuming groups of three :
Is it ok to have group D as described or should I buy more mosfets to get even better matching.
I used a 24 volt supply and a 30 ohm 30w resistor to get these readings. No heat sinks and took reading after 6 minutes.
I bought 10 9610's and was able to get a group of four at 4.1 Vgs.
I used a 24 volt supply and 2k resistor. Reading stabilized after 2 minutes.
The 240's did get quite hot but the 9610's hardly warmed up at all. Is this normal?
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