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FET Electrical Performance

10/25/1999 6:59 PM
Scott	FET Electrical Performance I have been working on a clean boost circuit and have been experimenting with the 2N5457 FET. With a 2.2K drain resistor, a 470 ohm source resistor, a 1M gate pulldown resistor, a 20 uF source resistor bypass, and a 9V supply, I get 5.4V at the drain. This should be about right. When I feed it with a .25V sine wave, I get a 1V sine wave out at the drain for a gain of 4, which is fine for my intended purpose. The problem is that the distortion is 1.5% THD at the 1V out, as measured using an HP 200CD oscillator and an HP 334 distortion analyzer. The test equipment is known to operating correctly. What is the typical distortion performance of these devices? I mainly work with tubes, so I have no idea what it should be.

10/25/1999 6:59 PM

Scott

FET Electrical Performance

I have been working on a clean boost circuit and have been experimenting with the 2N5457 FET. With a 2.2K drain resistor, a 470 ohm source resistor, a 1M gate pulldown resistor, a 20 uF source resistor bypass, and a 9V supply, I get 5.4V at the drain. This should be about right. When I feed it with a .25V sine wave, I get a 1V sine wave out at the drain for a gain of 4, which is fine for my intended purpose. The problem is that the distortion is 1.5% THD at the 1V out, as measured using an HP 200CD oscillator and an HP 334 distortion analyzer. The test equipment is known to operating correctly. What is the typical distortion performance of these devices? I mainly work with tubes, so I have no idea what it should be.

Replies:

R.G. 1.5% THD from a single FET gain sta... -- 10/25/1999 7:27 PM