Bread-and-butter components for the electronics hobbyist

It seems like every time I work on a project, I learn about another "bread-and-butter" component that I ought to keep plenty of on-hand. I wonder if there would be interest in sharing examples of people's favorites. I'd like to take as granted that one should have a variety-pack of resistors and capacitors, and focus more on ICs. Is this even a list that is worth compiling, or is it the kind of thing where everyone's list will be a little different depending on what they do?

Some things that come to my mind:

PNP and NPN BJT transistors. I have always used the PN2222 and PN2222a, but there are probably better, more modern choices. You can't beat the price.

555 timer IC.

A general-purpose op-amp. I think the LM741 is the old standby, but I have heard some people say it's dated, and there are much better options. Sparkfun sells the LM358, but I'm not familiar enough to judge. The 358 appears to be rail-to-rail, which si a good thing.

Opto-isolator/coupler. I use the LTV816, because that's what Sparkfun sells and I figured that means it can't be too bad. It doesn't have an accessible base leg, and it's not particularly high-speed, but for many basic purposes, I think it works well. When I first got into electronics, I didn't appreciate the benefits of galvanic isolation; now I live by it. Mis-matched grounds and unintended impedance interactions are the bane of my existence.

I have found good uses for a solid-state relay when replacing manual switches with computer-controlled ones. The relay's usage overlaps a little with the opto-isolator, but a main advantage, IMO, is that they can be purchased NO or NC, so that you can control what the relay's state will be when the control circuit is un-powered. I don't think you could have a NC optoisolator. I like the CPC1218 (Normally-Open) and CPC1219 (Normally-Closed). One nice thing about these is that they are entirely self-contained, so there is no need for supporting hardware like a current-limiting resistor on the control circuit. This is a good thing if you, like me, have a habit of accidentally blowing up your opto-isolators by accidentally forgetting the current-limiting resistor.

I would love to hear anyone's feedback on other "fundamental" components, as well as any feedback on better parts than the ones I've listed above.

4N35
http://measure.feld.cvut.cz/groups/edu/osv/4n35.pdf
LM339

LM3900
http://www.ti.com.cn/cn/lit/ds/symlink/lm3900-n.pdf
H11F1
https://www.fairchildsemi.com/ds/H1/H11F3M.pdf
IRL540

ULN2803
http://www.ti.com/lit/ds/symlink/uln2803a.pdf
TIP122

TIP127
http://www.fairchildsemi.com/ds/TI/TIP125.pdf
2N5088

I have been Arduino-ing since Fall of 2010, and here's the kind of parts commonly used so far.
N-channel & P-channel FETs, NPN & PNP transistors for muxing LEDs and relay coil/motor drivers.
Optos - if you are not totally isolating power supplies & Gnds, there is not much use for these.
555 - not much use with the uC providing control & timing signals.
TPIC6B595 shift register - really useful high voltage, high current shift register.
'328P-PU and '1284P-PU microcontrollers and parts for basic standalone designs - 10K resistor, 16 MHz crytal, 22pF caps, 0.1uF caps. 1uF and 10uF electroytic caps.
Diodes for coils/motors.
H-bridge chips for motors, stepper motors.
5V, 7.5V, 9V, 12V wallwarts.

Outside of that, I think you'lll parts will really be project dependent.
LEDs, current limit resistors, MAX7219 for display projects.
Pots for creating analog levels if you need to read a variable voltage for something.
Rotary encoders, push buttons if you need digital pulses.

CrossRoads:
Optos - if you are not totally isolating power supplies & Gnds, there is not much use for these.

This is a good point. Most of my Arduino projects have involved interfacing with existing hardware, so isolation has been crucial. That's probably not the norm, though.

555 - not much use with the uC providing control & timing signals.

Also a really good point.

'328P-PU and '1284P-PU microcontrollers and parts for basic standalone designs - 10K resistor, 16 MHz crytal, 22pF caps, 0.1uF caps. 1uF and 10uF electroytic caps.

LOL. Never forget the Arduino itself, right?

Hi
4k7, 10k resistors for pullup, (100's)
10k pots for simulating analog inputs
Red and other colour LEDs.(100's)
Tactile buttons

All sourced on ebay for pennies/cents if you look at auction and free postage items.

The total list sounds a lot, but it nice to be able to reach out and get a component fro your parts box when you need it.

Tom.... :slight_smile: