purpose of TL081 in this circuit? - LowRippleHVsupply2.jpg (0/1)
 

Hi all,

I found this schematic on the web, and can't quite understand what the
TL081 op amp does. Obviously, it's some sort of ripple reducer, but
what does it do and how does it work?

The authors ISP returns errors with the 2 published email addresses
on the website.

The entire web page is he

http://charliethompson.50megs.com/Lo...eHVsupply.html

Thanks,

M

Mebart wrote in message ...
Hi all,

I found this schematic on the web, and can't quite understand what the
TL081 op amp does. Obviously, it's some sort of ripple reducer, but
what does it do and how does it work?

The authors ISP returns errors with the 2 published email addresses
on the website.

The entire web page is he

http://charliethompson.50megs.com/Lo...eHVsupply.html

Possibly used as a gyrator?

N

well, personally i would add a TVS (transient Voltage Suppresser) and
maybe even a Zener to help protect that op-amp from an inrush of
voltage that would destroy the op-amp..
putting that aside.

Yes, I noticed that the high voltage was pretty close to the op amp
and that a leaky cap or a sudden application or removal of the power
might cause a problem.

Thanks for commenting.

M

Mebart wrote:

well, personally i would add a TVS (transient Voltage Suppresser) and
maybe even a Zener to help protect that op-amp from an inrush of
voltage that would destroy the op-amp..
putting that aside.

Yes, I noticed that the high voltage was pretty close to the op amp
and that a leaky cap or a sudden application or removal of the power
might cause a problem.

Thanks for commenting.

Clamp diodes from the relevant points to the op-amp's supply rails would
be an advisable addition.

Graham

Mebart wrote:
Hi all,

I found this schematic on the web, and can't quite understand what the
TL081 op amp does. Obviously, it's some sort of ripple reducer, but
what does it do and how does it work?

The authors ISP returns errors with the 2 published email addresses
on the website.

The entire web page is he

http://charliethompson.50megs.com/Lo...eHVsupply.html

Thanks,

M

well, personally i would add a TVS (transient Voltage Suppresser) and
maybe even a Zener to help protect that op-amp from an inrush of
voltage that would destroy the op-amp..
putting that aside.

what the op-amp is doing is simply using the inverting input signal
back to the source to cancel the effect there for, a high gain op-amp
is generally selected for this application because afterwards the
end results will be small.
this has also been noted in some doc's as an electronic/active capacitor.
personally, i wouldn't use it but that's me!