Parts/Components you always keep on hand.

Hey everyone!

I am fairly new to DIY/design (and relatively new to this forum, I think my post count is maybe 2 as of writing this) and wondering what parts would be good to keep on hand. Of course there are various resistors, caps, diodes (including LEDs,) jacks, and pots. I also have a few breadboards lots of wire, and since I’m focusing on euro specifically, a dedicated euro power supply for the breadboards. Beyond that, what components do you keep stock of? I want to order/build up a small stock of common components to have at the ready when inspiration strikes, rather than having to wait several days for an order.

Besides the above, I’m thinking:
various BJT and JEFT Transistors (any specific/interesting ideas on these welcomed)
Decade or other counter chips
Op Amps
A couple different vactrols

Right now I’m planning on ordering a bunch of parts found in the mki x es.EDU BOMs, but I’m wondering if there’s anything else useful out there that I might not be aware of yet.


This doesn’t exactly answer your question, but if you are planning on doing a lot of breadboarding these may save you some hassle and frustration:


Wow, that’s awesome though. I was not aware of those…I’ve already become frustrated with the jacks coming out of the breadboard. Thank you!

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in my own experience, as someone who hasn’t had to manufacture or mass-produce (at any scale) any of my electronics projects, it’s better for me to order what i’ve needed (this includes extra parts for mistakes when reflowing surface-mount boards). over time, this has led to a surplus of different parts that are useful to me in my projects and that kind of naturally selects my “go-to” components that i commonly need. i feel whenever i’ve purchased components that i didn’t have a concrete use for, they sit on a shelf and collect dust.


I agree with @murray about ordering a little extra of whatever you’re working on and then just keeping it on hand. If you are pretty sure you’ll be using more later, you can order extra and probably get a quantity discount. Also try to keep an eye on what seems like it might be hard to come by later – I didn’t know it at the time but now I’m super glad I ordered a few teensies before the global shortage.

I would also try to keep buffers and some basic amp chips (like LM386) or anything that will help you handle impedance issues and amplification. And I like having an assortment of the chips used in the circuit portions of Nicolas Collins’ Handmade Electronic Music (hex inverter, quad NAND, shift register).


I find it helpful to have components that make adding stuff to the breadboard easier, like DIP IC sockets (minimize bent pins when swapping out through-hole ICs), 2.54mm pitch female pin headers (especially if you start adding microcontrollers like Teensy/Daisy, but also good for board-to-board connections, etc), and screw terminals (for adding threaded wire from power supplies, speakers, etc).


I’d agree you are on the right track. I always like to have a decent resistor and capacitor set. Only a couple of each value normally gets me out of trouble.

I think I would consider “standard” components like:

  • basic dual opamps 4558, tl072
  • regulators lm7805,lm7812 etc
  • 1n4148 diodes work for a lot of different diode needs
  • I always seem to be missing that one pot value I need for something, though they are pricier to keep a big collection of.

Hope that helps!


solder wick/braid

More importantly than the parts are the soldering supplies. I carry plenty of:
0.38mm solder (smd work)
0.8mm solder (through-hole work)
For soldering, I now have a fancy station but used to use an old Hakko 936. Regardless, the tips remain the same:
1.2mm chisel tip (0603/0805 smd work)
1.8mm chisel tip (larger smd and through-hole work)
2.2mm bevel tip (drag soldering and heavy duty stuff)

For passive parts (resistors/capacitors/diodes), I recommend buying 100 of every non-weird part, especially when using Mouser and the like. Quite often, the price difference between 10 and 100 is absolutely tiny. This will let you build up a library of components. I pretty much only do SMD stuff these days, so I have three “sample books” which I fill with the excess parts. I have one for resistors, one for caps and one for ICs and various other bits and bobs. Super handy!

If you’re doing eurorack SMD stuff, get a load of 1n5819HW diodes.


If you really get into building eurorack you will need lots of:

2n3904 transistors (thruhole) or MMBT3904 (SMT)
Tl072, tl074, MCP6002, MCP6004 opamps
1n914 or 1n4148 silicon and 1n5819 schottky diodes
AMS1117-3.3 (3.3v) and AMS1117-5 regulators for microcontroller based designs
3mm thruhole LEDs in your favorite colors
10k linear pots - small footprint RV-09 are widely used
knobs for pots
PJ-301 mono jacks - you will go through a LOT of these

I almost always prototype with .1" spaced plated through pad boards because they can accommodate DIP chips and they work very well for 0603 size SMT parts as well. I put DIP parts on the panel side and the SMT parts on the back side - with planning you can put quite a few pots, jacks, a few DIP packages and a lot of SMT parts onto an 8HP size board. I designed an 8HP protoboard and blank panel specifically for this. The PCB is layed out with a 10 pin header, 1n5819 polarity protection diodes and power supply filter caps and has a GND track around the outer edge to make things a bit easier to wire up.

These are fairly inexpensive to order from Chinese PCB houses like JLCPCB ~ $1 each plus shipping.

I’ve had good luck buying jacks, pots, resistors, capacitors, diodes, regulators and transistors in bulk from Aliexpress and they are much cheaper than buying from Digikey if you don’t mind slow delivery. I don’t buy opamps or microcontrollers there anymore because I’ve gotten some bad and fake parts. The more expensive the part is the more likely it is it will be faked - especially now with widespread semiconductor shortages.