Re: [EE]: Bi-Directional 20A current shunt Using Single supply OPAMP

Nothing is set in stone.

However, we are on the road for an additional 5 weeks and I have a small
selection of parts that includes a shunt, LM324, esp8266, thru hole vero
board etc and like to think I am resourceful.  There maybe electronic
stores along the way with a limited range of components. (JAYCAR and
Altronics)

While investigating current sensing solutions I discovered there are many
purpose built devices but acquiring them without a fixed address is
challenging and they are SMD.

Curious if the diode solution to lift the reference is viable as the
challenge of using opamps without a split rail seems to come up often and
LTspice seems to suggest it is.  I can just make it and find out, I just
dont have the luxury of breadboard, Bench PSU, Scope etc so I was
interested to know if the solution has merit or has been used in the wild.
I have not found any such examples.

Jusin

On Fri, Sep 12, 2025 at 3:35 PM Clint Jay <[email protected]> wrote:

> Is the shunt set in stone or could you consider one of the current sensors
> with built in conditioning like the INA2xx range?
>
> Clint. M0UAW IO83
>
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
>
>
> On Fri, 12 Sept 2025, 03:46 Justin Richards, <[email protected]>
> wrote:
>
> > I would like to condition the output of a 1.1mV/A current shunt to drive
> > the analog input of a WEMOS D1 Mini (0 - 3.3V).
> >
> > The target application is easy monitoring (wifi) of anything 12V with an
> > Anderson plug. i.e. Vehicle to Caravan charge line, Solar Panel to
> Battery,
> > Battery to Electric Blanket/Fridge etc.
> >
> > The device is to be powered from the circuit it is monitoring which will
> be
> > around 12.8V.
> >
> > I am a long way from a bench so have resorted to LTspice.  The attached
> > circuit (5KB so I hope it gets thru) appears to behave exactly as
> desired.
> >
> > However, 2 diodes in series to raise the reference to allow for the
> > negative swing seems to work in LTspice but I am curious what others
> think
> > about this approach.
> >
> >
> > Justin
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > https://mailman.mit.edu/mailman/listinfo/piclist
> >
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> https://mailman.mit.edu/mailman/listinfo/piclist
>
-- 
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
https://mailman.mit.edu/mailman/listinfo/piclist