Let's amp up the discussion on OpAmps (Operational Amplifiers) and how they work

[mixedgas]

Ha! That is funny. I didn't notice that.

I'm the reason Sheldon is a vexillologist in his spare time. Flags were a hobby in 5th-6th grade.

Steve

[lasermaster1977]

Oh, I don't know if it is such a problem... Seems GAP and his team solved that one too..

Depends where the breakpoints in the diode array are located.

A feller could have himself a pretty good time in Vegas with these:

http://www.philbrickarchive.org/k3_s...components.htm

The theory was known:

http://www.philbrickarchive.org/wide...multiplier.pdf

Mask defined math using electron beams.

https://www.radiomuseum.org/forum/ge...nd_qk_256.html

Steve

Very interesting links, thanks again Steve.

[Greg]

Oh wow. Yeah, those are whopping interesting links. Thanks Steve. I'm checking if these devices were available at the time of the development of radar. Oh yeah, it's right there.

[dchammonds]

I'm surprised Dean hasn't commented on this thread. He knows all kinds of stuff about op-amps. Whenever I needed a schematic for something, I asked him. In high school he made his own phono preamp with the RIAA equalization and a headphone amp. He made a really nice electric guitar preamp for me, that can do stereo (a pickup in each channel) that has a high input impedance to avoid the high frequency roll-off that would otherwise be caused by the inductive reactance of the pickup coils.

OK...

I was first introduced to op-amps via an electronics correspondence course that I took in high school around 81. Around the same time, Mom gave me a
DIY Sinclair ZX-81 computer kit before I even knew I wanted one. Learning Ohm's Law was one thing, but dealing with inductive and capacitive reactance
and total impedance in an AC circuit using a two-dimensional number system was mind blowing. With a little inspiration from an op-amp cookbook and
a desire to try predicting the behavior of a circuit before wiring it, I designed a cheap phono preamp for headphones. I programmed my ZX-81 to graph
a math model of the phono EQ and tone control design like a TI graphing calculator well before such a thing existed.


All those bike trips to Radio Shack! Fortunately, there was a record store next door so I could kill two birds with one stone.

I never got around to putting it in a case. Not pretty to look at, but it sounded good!

[james]

I still remember your Koss Pro 4X headphones. The low end was insanely over emphasized and they were so sensitive you could plug them directly into an electric guitar with passive pickups, no amplification, and clearly hear the guitar.

[HankLloydRight]

Had me worried there for a moment -- looks like that's only for the TL084CD version, and none of the others.

Luckily I use the TL084CDN version which is still in production.

I can't imagine TI ever killing the entire TL084/TL074 production. I've never been able to find a compatible replacement that can do +/-10v.

[HankLloydRight]

Hi, Hank!
Luckily, I've learned to order SMDs by the 100s, because of the price breaks and shipping costs for small orders. I'm good on TL084's for life! 😎
BR
Roj

Great! I'm not to the point of doing SMT assembly yet, so I'm still beholden to current stock levels.

[buffo]

This thread reminds me of the "Intro to Op-Amps" presentation that Andrew Berry did at SELEM back in 2018. I wish someone had recorded that one!

Adam

[Bradfo69]

This thread reminds me of the "Intro to Op-Amps" presentation that Andrew Berry did at SELEM back in 2018. I wish someone had recorded that one!

Adam

I think I may have that. Didn't I transfer the SELEM videos I've come across to you while we were on the cruise?

[buffo]

Didn't I transfer the SELEM videos I've come across to you while we were on the cruise?

I didn't have enough space on the external drive for all the files.

Maybe I can get those from you at SELEM this year. (I'll bring a larger drive!)

Adam