📙: Dual Op Amp =|>-

2017-04-04T22:28:39Z

Dual Op Amp =|>-

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* https://en.wikipedia.org/wiki/Operational_amplifier
* http://www.ti.com/lit/ds/symlink/lm358-n.pdf
* http://pdf1.alldatasheet.com/datasheet-pdf/view/8674/NSC/LM358M.html

== Phase shifter circuit ==
(From Richard Karlquist)

Here is a well known op-amp phase shifter. I am surprised no one has posted it yet, so I guess I will have to. The circuit will have 90 degrees phase shift at:

FREQ = 1/(2*PI*R3*C)

At low frequencies it has 0 degrees of phase shift and at high frequencies it has 180 degrees of phase shift. By making R3 a pot, you can vary the phase at a given frequency from nearly 0 to nearly 180 degrees. Since you want to work at 1 MHz., you will need to use a high frequency op amp, like the Burr-Brown OPA620.

<pre>

R1=R2 |---\/\/\/\/\\/\--|
| R2 |
| |
R1 | |\ |
| INV | \ |
INPUT --------\/\/\/\/\/\/----------| \ |
| | \ |
| | \-------- OUTPUT
| R3 | /
| NON-INV | /
|---\/\/\/\/\/\/----------| /
| | /
| |/
|
|
------- C
-------
|
|
|
|
GROUND
</pre>

LM358 - Revision history

📙: Dual Op Amp =|>-