Re: simple 150uA constant current supply


"Dave" <daveh@xxxxxxxxxxxx> wrote in message
news:47eff3df$0$1399$c5fe31e7@xxxxxxxxxxxxxxxxxxxxxxx
Thanks Martin but, it's not homework, I don't have any space for an IC and
this is battery powered.
I can only spare about 30uA to 'generate' this supply.
Thanks
Dave

"Martin Griffith" <mart_in_medina@xxxxxxxx> wrote in message
news:o3svu3dhvijcaoq14kjm1v2ll6o9qapo8m@xxxxxxxxxx
On Sun, 30 Mar 2008 20:49:36 +0100, in sci.electronics.design "Dave"
<daveh@xxxxxxxxxxxx> wrote:

I would like to find the simplest way to provide a constant current of
around 150uA (+/-20%) at around 2V.
This needs to be discrete components rather than IC and should not
involve
pulse width modulation.
The simplest form I thought of was a 3v voltage reg with a 20K resistor
between it's 'reference ground' and the output but this seems clumsy.
Anyone ?
Thanks
Dave

Sounds like a homework assignment, but I'd start off with a 150V rail
and a 1Meg resistor


martin



An IC is actually the simplest and smallest way to build this National LM134
but it does require at least 1vdc to operate.

Bob


.

Relevant Pages

  • Re: simple 150uA constant current supply
    ... I can only spare about 30uA to 'generate' this supply. ... Uhm, so you contemplated a regulator chip but don't want an IC. ... The simplest form I thought of was a 3v voltage reg with a 20K resistor ...
    (sci.electronics.design)
  • Re: simple 150uA constant current supply
    ... pulse width modulation. ... The simplest form I thought of was a 3v voltage reg with a 20K resistor ...
    (sci.electronics.design)
  • Re: simple 150uA constant current supply
    ... pulse width modulation. ... The simplest form I thought of was a 3v voltage reg with a 20K resistor ...
    (sci.electronics.design)