Topic 43: JFET Small Signal Amps

In this video we examine the small-signal model for the JFET and analyze the common source amplifier configuration. Several analysis examples are discussed and the design of a simple pre amp or booster/overdrive is presented. The transconductance equation for the JFET is also derived at the end of the video.

[@AnalogDude_]

Hi there, i wanna limit inrush current to the "big" capacitors after the bridge rectiefier using mosfet's (witch is what i got at hand). If you would measure the voltage with a LM393 comparator and a CD4013 or and gate as latch to open the N channel mosfet on the positive rail fully. How would i apply this "trigger" to the mosfet on the negative rail? .... with close to 40 Volts difference. It works on the simulator, accept due to high voltage difference the mosfet on the negative rail is opening much faster (if you would use a capacitor delay). How can i tackle this?

[@Electronics4Guitar]

If I get time I’ll try to think of something. No promises. I’m sure you’ll figure it out though.

[@AnalogDude_]

@@Electronics4Guitar i tried various things, like transistor Totem Pole, to shift the voltage difference, it works, but the same problem, it would be cool if it could be done with a single timing capacitor than one on each of both rails.