My version of the G = 1000 low noise measurement amp (for Ikoflexer)

[deanoUK]

Fantastic. Just paid. Thanks.

 

[EUVL]

Office will process tomorrow.


Patrick

 

[EUVL]

All PCBs shipped and tracking numbers sent by email.
All credit to the office staff in HK.


Patrick

 

[jackinnj]

one is pretty, the other not so much:

 

[EUVL]

Both now working ?

Happy New Year,
Patrick

 

[1audio]

For the 1 Ohm resistor wouldn't a current sense resistor like this work OK? http://www.mouser.com/ds/2/414/LR-469703.pdf 10 cents vs. $20. If its about low noise I think the excess noise of any 1 Ohm resistor at 1 mA will be in the mud anyway.

If there is a next run of boards I'll be interested.

 

[basreflex]

the value of C5 is way too low. it should have an low impedance for noise in series with the source, so similar to the 1 ohms resistor it's impedance should be low.
now it is 1.5k at 100 hz.

 

[scott wurcer]

the value of C5 is way too low. it should have an low impedance for noise in series with the source, so similar to the 1 ohms resistor it's impedance should be low.
now it is 1.5k at 100 hz.

No, input pole is 1uF and 56M Ohm, .003Hz.

 

[scott wurcer]

For the 1 Ohm resistor wouldn't a current sense resistor like this work OK? http://www.mouser.com/ds/2/414/LR-469703.pdf 10 cents vs. $20. If its about low noise I think the excess noise of any 1 Ohm resistor at 1 mA will be in the mud anyway.

If there is a next run of boards I'll be interested.

Yes, it should be fine I think.

 

[jan.didden]

For the 1 Ohm resistor wouldn't a current sense resistor like this work OK? http://www.mouser.com/ds/2/414/LR-469703.pdf 10 cents vs. $20. If its about low noise I think the excess noise of any 1 Ohm resistor at 1 mA will be in the mud anyway.

If there is a next run of boards I'll be interested.

YGM

 

[EUVL]

I think we still have ~5 boards left.
Take a week to order more. So no issue.
Getting someone to check payment, pack and ship is more troublesome.


Patrick

 

[1audio]

Should I start a list for the next batch?

Demian 1 board

 

[EUVL]

Thx,
Patrick.

 

[EUVL]

We also built a special version where the JFET is replaced by a TO92 test socket.
The latter sits on a stackered board which provides mechanical support.
We used a Version 1 board which had a layout error, so no use otherwise.

Now we can screen JFETs for noise.


Patrick

 

[EUVL]

Demian,

Please PM me your email & postal address.


Thx,
Patrick

 

[EUVL]

While we are at it, may I also send you one (as a small gift from XEN), Scott ?
Your postal address is still as before ?


Patrick

 

[jackinnj]

If you are going to test a lot of devices, a good idea to replace R3 with a potentiometer and a series resistor, as you did to limit the current into the opto-coupler's LED (with R2a).

 

[scott wurcer]

While we are at it, may I also send you one (as a small gift from XEN), Scott ?
Your postal address is still as before ?


Patrick

I'll get you my address since I'm retired now. They removed my email account even though someone went to great lengths for that not to happen.

 

[EUVL]

Noted,
Patrick

 

[EUVL]

PCBs on their way to Demian and Scott by normal Air Mail.


Patrick