Mosfet Gyrator using the IRF840

[ikoflexer]

It shows about 10dB better psrr for gyrmos, at about 100-120Hz. The .trans show ripple though, is smaller for multires. That to me, is a bit odd.

[revintage]

Remember I changed from 10ohm to 33ohm. Before that multires was ca 2dB better than the other two at 100Hz.

[Bas Horneman]

IRFP240

Just realized that I have some of those because I got some extra for the Zen V9. Way cheaper if I remember well. So I'll use those...much cheaper than the 20N50D.

[bananatuan]

I'm working with mosfet gyrator by schematic as attachment

R1, R2 330k Ohm
C1 5.6uF
D1 ZD15
R3 150 Ohm / 5W
Q1 IRF840
At the moment , i want to get :
- Vout = 100VDC when Vin = 120 VDC ( after bridge rectifier)

The question is that how do I adjust R1, R2 to get exactly the above Vout voltage ? Pls kindly advise. Tks

[ErikdeBest]

The gyrator is not a regulator in the sense that it will have an absolute (exact) output voltage, so if you want exactly 100V at the output under different operation conditions, it will not work. Still, I think it is possible to accomplish a relatively constant output voltage in class A operation, but to do some calculations on it one needs to know how much current your circuit will be drawing (this current goes through R3, what causes a voltage drop... )