[sdiy] 741 null offset

[pata at ieee.org]

Hi David and the Lists!

Offset null terminals of types 741, 081/071, 356, 301/307, 308/312 must
be kept open unless using for nulling offset, frequency compensation, etc.
In case of using offset null terminals of 741 correctly, not only
nulling offset but also a little faster than as their terminals left open.
Because operating current of first(input) stage is added a little.
(really very little...)
The other hands, if nulling terminals connected not suitable, such as
long wirings, short circuit to GND or power supply lines, cause damage
to the OP amps.

*appendix*
About 35 tears ago, many engineers tried to improve IC OP amps
charactoristics (mainly frequency response) with using offset null pins.
Even 741 can be improved its dynamic response with 2 capacitors
connected to the offset null pins.
This was invented by Mr.Michio Okamura, discussed with Dr.J.Greame via
airmail (NOT E-mail !).


David Ingebretsen wrote:
> I've been unable to find an answer in my books, datasheet, or online.
> 
> Does one have to connect the offset null pins on a 741 to anything? What
> happens if you don't connect them?
> 
> David
> 
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> 

-- 
===================================================
KATAYAMA, Takuya
Muse Music Synthesizer Laboratory, Japan