Analog Devices AD741KH High Accuracy Op Amp TO-99 Metal Cap
Moderators: rjlittlefield, ChrisR, Chris S., Pau
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Analog Devices AD741KH High Accuracy Op Amp TO-99 Metal Cap
Still playing with my 35mm Macrophoto. I wasn't sure how to remove the cap so I drew up a fixture and 3D printed it to hold the cap and used a parting tool on my lathe to remove it. Looks like I didn't get everything, o'well. I can still clean it up but I'm happy with the results so far. I could of taken a few more images for the stack too.
Much larger version here;
https://squattingdog.smugmug.com/Semico ... -CmhK9M4/O
Much larger version here;
https://squattingdog.smugmug.com/Semico ... -CmhK9M4/O
That old 741 brings back memories I have used many of them, they were/are the most versatile OP AMP ever! Fullgar (sp) invented the ua741 at Fairchild and Bob Wilder tried to one up him with the LM101 at National. Then George Erdi came up with the ua725 precision version op amp using a "Cross Coupled Quad" layout which reduced thermal feedback, process variations and input device mismatch all at once. The layouts are done with Rubylith and Exacto blades backs then, Fond memories of those days
The large metal area is the feedback capacitor, 40pF I recall.
Very clever fixture to remove the TO-99 lid
And nice pictures too
Best,
Mike
The large metal area is the feedback capacitor, 40pF I recall.
Very clever fixture to remove the TO-99 lid
And nice pictures too
Best,
Mike
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
- Contact:
I see the first Op-Amp was produced in 1941
I met 741's 30 years after that. I was surprised/horrified to see they still get a mention on the current Electronics school syllabus!
Good job with the Lomo - and the parting tool. Somewhere I have one of those cans I made a mess of with a hacksaw..
I met 741's 30 years after that. I was surprised/horrified to see they still get a mention on the current Electronics school syllabus!
Good job with the Lomo - and the parting tool. Somewhere I have one of those cans I made a mess of with a hacksaw..
Chris R
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
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... I could of easily placed a piece of fine sandpaper on a surface plate and removed the cap. I have a tendency of over doing just about everything I do. <g>ChrisR wrote: Somewhere I have one of those cans I made a mess of with a hacksaw..
-JW:
Last edited by Smokedaddy on Thu Dec 28, 2017 9:37 am, edited 2 times in total.
Smokedaddy,
Large 6' square light tables with grids, wrapped with Rubylith sheets and drafting tools were the norm way back then, long before computers came into play
Chris,
Op Amps, or Operational Amplifiers, were/are a fundamental building block for analog computers, originals were built with tubes. They got their name from operational analog computations including summation, integration and differentiation, this was relatively easily with these devices. Burr-Brown and Philbrick are companies that come to mind in the early days of Op Amps.
Best,
Mike
Large 6' square light tables with grids, wrapped with Rubylith sheets and drafting tools were the norm way back then, long before computers came into play
Chris,
Op Amps, or Operational Amplifiers, were/are a fundamental building block for analog computers, originals were built with tubes. They got their name from operational analog computations including summation, integration and differentiation, this was relatively easily with these devices. Burr-Brown and Philbrick are companies that come to mind in the early days of Op Amps.
Best,
Mike
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
- Contact:
I was a manual draftsman in a few disciplines for 20 years or so up until I got involved with AutoCAD in the late 80's.mawyatt wrote:Smokedaddy,
Large 6' square light tables with grids, wrapped with Rubylith sheets and drafting tools were the norm way back then, long before computers came into play
On another note, I would love to know how to intricately etch brass or aluminum cylindrically. I've been trying to find specific (like exact) directions for quite a few months. I did read about using PNP Blue but nothing intricate or cylindrical objects.
-JW:
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
- Contact:
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- Posts: 88
- Joined: Mon May 11, 2015 9:21 pm
- Location: Hocking County, Ohio , USA
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
- Contact:
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- Posts: 1965
- Joined: Sat Oct 07, 2006 10:16 am
- Location: Bigfork, Montana
- Contact:
Thought I'd make a stereo pair version. Best viewed with stereo glasses. A larger version is here;
https://squattingdog.smugmug.com/Stereo ... -C4pjGK7/O
-JW:
https://squattingdog.smugmug.com/Stereo ... -C4pjGK7/O
-JW:
My first encounter with a 741 op amp was in 1970. There were rough plans in Scientific American for a seismograph. The op amp circuit was part of the detector feedback loop that drove the chart recorder’s pen. I cobbled it together with a clock motor to advance the paper and a slot-car motor to move the ball point pin. Amazingly after a few weeks of fiddling it all worked. I recorded earthquakes in China and South America. When I went away to college my dad kept it running for several years. His letters from home were often written on the back of the output tape. Fond memories!
Thanks for posting!
Keith
Thanks for posting!
Keith