Bias voltage for SD2942 48V 350W pallet

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fyber
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Bias voltage for SD2942 48V 350W pallet

Post by fyber »

Hi Guys

Does anyone know what the bias voltage should be for the gate of this transistor/pallet board? I know the current is meant to be 200mA MAX but need to work out the voltage

Any help greatly appreciated!
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pcs
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Post by pcs »

It is different for every transistor. You set them to get the current right.

That is why you have trimmer on each board.
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stylzmovement
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Post by stylzmovement »

Hi,
Where do you measure the bias voltage or current from ?
Is it the voltage that's important?
Or is it the current?
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pcs
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Post by pcs »

It is of course the current.

Now how do you measure current? With current meter of course, make sure drive is disabled.
Start with zero voltage and slowly increase while observing current.

Marko
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stylzmovement
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Post by stylzmovement »

I have a few more questions,
How do you disable the pallet to perform this test?
Where on the pallet do you measure from?
Is it that the positive probe is placed on the +5 and the negative on the ground
Meter in milli amp mode?
Is that correct?
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pcs
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Post by pcs »

There is nothing to disable, just do not apply any RF drive when you do this.

Next connect amp meter in series with power supply and measure away.
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stylzmovement
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Post by stylzmovement »

2 transistor on an amp module , each one will need to be bias separate?
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pcs
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Post by pcs »

You have to disconnect drain of the tested fet and connect it separately to power supply via amp meter.

How exactly you can disconnect drain depends on the pallet, most give an option to do that via jumpers or have drains separated anyway.
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Marko - PCS Electronics
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