This popular gyrator smoothing choke works well in a positive supply. Now I'd like to use it to smooth a negative bias supply where the positive of that is referenced to HT ground. So can I just simply put this "two wire" gyrator in line with the bottom negative wire instead of the top wire? Like I could if it were a real choke? IOW simply flip it upside down. are there any polarity issues with doing that?
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I'm looking at lower voltage (50-100V) P-channel mosfets that are somewhat similar to IRF820, for converting this circuit to a negative leg gyrator for an unregulated bias supply. I noticed that most N-channel mosfets have a much lower Rds (drain source on resistance) than the IRF820, most are well under .5 ohms whereas the IRF820 is a whopping 3 ohms.
Is there an advantage in this circuit to using a high Rds device? Or can I basically use any N-channel power mosfet as long as its Vds is over the voltage I'm using?
The reason I ask is because there are very few P-channel fets with an Rds of 3 ohms but a great many under .5 ohms. Is a device with high Rds critical in this circuit or not is my question I guess. Or was the IRF820 simply chosen here because the author had some of those on hand. Newark has a lot of P-channel mosfets on sale with low Rds.
Is there an advantage in this circuit to using a high Rds device? Or can I basically use any N-channel power mosfet as long as its Vds is over the voltage I'm using?
The reason I ask is because there are very few P-channel fets with an Rds of 3 ohms but a great many under .5 ohms. Is a device with high Rds critical in this circuit or not is my question I guess. Or was the IRF820 simply chosen here because the author had some of those on hand. Newark has a lot of P-channel mosfets on sale with low Rds.
