Magura said:That is not much for two channels. You are going to dissipate close to 300W of heat, if you stick to the 0R22, as in 3A bias.
I used something like 6 or 8 times that, and still I had it running at the wrong side of good.
Magura
I think you need to turn the bias down by x2 or even x4 until you get better heatsinks. Mebbe 1 ohms for the bias setting resistor (up from .22/.33)
well i still have the question as to why im getting voltage in the 30's to the gate of q2
im being told that its ok but im thinking there is a reason why mr. pass said it is supposed to be 4 volts to the gate of q2. im thinking q2 is going into overdrive because of the gate voltage. what do you think?
im being told that its ok but im thinking there is a reason why mr. pass said it is supposed to be 4 volts to the gate of q2. im thinking q2 is going into overdrive because of the gate voltage. what do you think?
I just looked at the IRFP9240 datasheet
http://www.irf.com/product-info/datasheets/data/irfp9240.pdf
Two things pop out:
Maximum source-gate voltage is 20V. You measured 0V on the gate which means you blew out the gates.
The gate threshold voltage i.e. where the FET turns on is -4V. You measure this from gate to source (not gate to ground)
But you've got one channel going well?
http://www.irf.com/product-info/datasheets/data/irfp9240.pdf
Two things pop out:
Maximum source-gate voltage is 20V. You measured 0V on the gate which means you blew out the gates.
The gate threshold voltage i.e. where the FET turns on is -4V. You measure this from gate to source (not gate to ground)
But you've got one channel going well?
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