#opamps — Public Fediverse posts

I can safely say that it's been a while since #DigiKey sold #resistors in pre-packed bags of 5 with included card labels. As their own brand. Made in Taiwan.

Or called themselves "Digi-Key Corporation".

More seriously, I found a bag of #components left over from my senior year of school, when we did our big final project. Mine was a computer-controlled slot machine. Components were seriously expensive then; I organized a group buy with 4 or 5 of my classmates through "Digi-Key", partly because they were cheaper than the local suppliers (see previous story about the "Two Weeks Ten Bucks" guys), but also because we could get quantity price breaks on stuff that was common between our #projects, like the 1 kΩ resistors. IIRC, the resistors cost about $0.30 each in the 5-packs, but the bag of 200 was *way* cheaper - about half that, I think.

These were ordered in 1997, so almost 30 years ago. In addition to #vintage resistors, I found ZTX549 PNP #transistors (still in stock at DigiKey today!), MJE2955T #PNP transistors (also still in stock!), 3 different brands of 741 #opamps, including made-in-Japan and made-in-Malaysia #NEC, TI ones from Taiwan and the Philippines, as well as #TI TL081CP and LM318P from Taiwan. Also a bunch of 74-series logic #chips and some weirder stuff, like a #Motorola MC14412, which is essentially a 0-600 bps (~baud) modem-in-a-chip.

So if you need some vintage components, hit me up 😉

#TexasInstruments #electronics #SupplyHouse #FoundAtHome

I found the culprit... It's the #TL072 that goes into phase reversal because the gate and trigger signals are -12V when low.
After swapping it with a #LM358, the output signals for trigger and gate, including the LEDs work as intended.
This took a lot of time to find out, but I've gained some knowledge now.
#PhaseReversal #OpAmps #BugFixing

I made a small voltage rail splitter using an #LM358 #OpAmp that I salvaged from an old motion detector.
I want to play around with #OpAmps and thought it would be nice to have a #circuit for creating a virtual ground reference with positive and negative voltages.
The boost converter is only for testing, I'll connect a 24V supply later.
Only thing I have to adjust is the inrush current.
I'll convert it to a soldered perfboard, too.
#electronics #diy #dualrail #powersupply #breadboard #KiCad

Using 7 dual #opamps (LM358) to generate PWM signals for driving a non-addressable RGB LED strip so that only one linear potentiometer is needed to sweep through the colours of the #rainbowFlag

Project inspired by
https://youtu.be/KMuTTQeQ4_c
in which @blitzcitydiy used a microcontroller to map a potentiometer to the range of hues

#PrideMonth #electronics #opampChallenge #LEDs

Three potentiometers control the duty cycle for pulse width modulation of the three colour channels of an RGB LED strip (non-addressable). The PWM signal is generated by #opamps (#LM358) configured as an oscillator and 3 comparators. An NPN transistor sinks the current for each of the LED colours.
#LEDs #electronics

Pulsating PWM using two #LM358 dual #opamps configured as a fast oscillator, a slow oscillator, and a comparator whose output is the source of one LED and the sink of another LED

No microcontroller required
#electronics #OperationalAmplifiers #LEDs