Question: Sampling resistor for measuring current value

[Zhong Pan]

Hello all,

Sorry to bother you guys again but I really need some quick help on this
issue.

I am designing a PCB circuit that gives specific current values to a
device. Unfortunately after the D/A converter I MUST use a voltage
amplifier for some reason, so I lose the information how much current
I am sending.

Previously I would just put a 1-ohm sampling resistor in series in
the middle of the trace and measure its voltage. But I am dealing
with high speed this time - although the frequency on the trace
is below 10MHz, I need to keep a very sharp rising edge that may
require GHz response.

My question: Will the action of putting a series resistor significantly
influence the high-frequency response? If yes, what do people do
in this situation?


--
Best regards,
Zhong mailto:zhopan77@163.com

 

how about use current probe?
Zhong Pan <zhopan77@163.com> wrote in message news:<1126667482.20040614223751@yahoo.com>...

Hello all,

Sorry to bother you guys again but I really need some quick help on this
issue.

I am designing a PCB circuit that gives specific current values to a
device. Unfortunately after the D/A converter I MUST use a voltage
amplifier for some reason, so I lose the information how much current
I am sending.

Previously I would just put a 1-ohm sampling resistor in series in
the middle of the trace and measure its voltage. But I am dealing
with high speed this time - although the frequency on the trace
is below 10MHz, I need to keep a very sharp rising edge that may
require GHz response.

My question: Will the action of putting a series resistor significantly
influence the high-frequency response? If yes, what do people do
in this situation?

 

[Zhong Pan]

Hi,

I've never used one before. Can you give me more detailed information?

Zhong

<laji_cn@yahoo.com> wrote in message
news:9382f229.0406151632.17c97df2@posting.google.com...

how about use current probe?
Zhong Pan <zhopan77@163.com> wrote in message
news:<1126667482.20040614223751@yahoo.com>...
Hello all,

Sorry to bother you guys again but I really need some quick help on this
issue.

I am designing a PCB circuit that gives specific current values to a
device. Unfortunately after the D/A converter I MUST use a voltage
amplifier for some reason, so I lose the information how much current
I am sending.

Previously I would just put a 1-ohm sampling resistor in series in
the middle of the trace and measure its voltage. But I am dealing
with high speed this time - although the frequency on the trace
is below 10MHz, I need to keep a very sharp rising edge that may
require GHz response.

My question: Will the action of putting a series resistor significantly
influence the high-frequency response? If yes, what do people do
in this situation?