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Example circuit for I/V conversion

S

Stephen Boulet

Jan 1, 1970
0
Can anyone point me to an op amp circuit that could be used to convert
3.24 mA DC/4.32 mAp-p AC current to a voltage?

Stephen
 
T

Tim Wescott

Jan 1, 1970
0
Stephen said:
Can anyone point me to an op amp circuit that could be used to convert
3.24 mA DC/4.32 mAp-p AC current to a voltage?

Stephen


Rf
___
.--|___|--.
| |
Iin -> | |\ |
----------o---|-\ | Vout = - Rf * Iin
| >--o-------
.---|+/
| |/
.-.
| |
| | Rf
'-'
|
|
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

That was too easy -- what did I miss?
 
B

Bob Monsen

Jan 1, 1970
0
Stephen said:
Can anyone point me to an op amp circuit that could be used to convert
3.24 mA DC/4.32 mAp-p AC current to a voltage?

Stephen

How about a resistor? You could follow it by an opamp buffer if you
needed lower output impedance.
 
S

Stephen Boulet

Jan 1, 1970
0
Tim said:
Rf
___
.--|___|--.
| |
Iin -> | |\ |
----------o---|-\ | Vout = - Rf * Iin
| >--o-------
.---|+/
| |/
.-.
| |
| | Rf
'-'
|
|
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

That was too easy -- what did I miss?

I really like the ascii circuit generator you used, by the way. I'll
check it out.

What *I* missed is that I needed it to be non-inverting. :( The common
mode voltage is going to be about 2.4 V instead of ground.

Stephen
 
T

Tim Wescott

Jan 1, 1970
0
Stephen said:
I really like the ascii circuit generator you used, by the way. I'll
check it out.

What *I* missed is that I needed it to be non-inverting. :( The common
mode voltage is going to be about 2.4 V instead of ground.

Stephen

What I didn't say was that your post was lacking detail, like inverting
vs. non-inverting, and what frequency AC, and whether you could stand
some non-zero input impedance to the thing.

If the frequency is low and you can't stand non-zero impedance then use
2.4V for "ground" and follow my circuit with another inverter. If you
can stand a non-zero impedance to ground then use Bob Monson's resistor
to 2.4V, possibly followed by a non-inverting amp that's also referenced
to 2.4V. If the AC frequency is high and you must have zero impedance
to ground then brush up your resume.

Etc.
 
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