The list below contains parts that would be common to a variety of circuits designs and experiments.
Transistors (BJTs)
Description Digikey Link
* BJT, NPN 2N3904G
* BJT, PNP 2N3906G
BJT, NPN, high gain BC548C
BJT, PNP, high gain BC557C
N-CH Logic Level FET, 55V, 47A, TO-220 IRLZ44
N-CH Logic Level FET, 30V, 40A, TO-220 FDP8878
N-CH Logic Level FET, 60V, 200mA, TO-92 2N7000RLRAG
Diodes
Description Digikey Link
* Signal Diode 1N4148
Voltage Regulator
LM317 adjustable regulator has an adjustable output voltage that can range from 1.2V to 37V, and a maximum output current of 1.5A. Two resistors are required to adjust the output voltage.
Description Digikey Link
Adjustable regulator LM317T
Logic ICs
74AHC series (or other series with 5V tolerant inputs). These devices are useful for interfacing 5V and 3.3V systems together.
Function Package Digikey Link
Quad NAND DIP-14-300 SN74AHC00N
Quad NOR DIP-14-300 SN74AHC02N
Hex Inverter (SCHMITT) DIP-14-300 SN74AHC14N
Quad XOR DIP-14-300 SN74AHC86N
Dual Timer (1V-15V Power Supply) DIP-14-300 TLC552CN
Single Timer (1V-15V Power Supply) DIP-8-300 TLC551CP
Op-Amps
Description Digikey Link
Single supply op-amp (3-15V) TLC272ACP
LEDs
Coming Soon
Resistors
1%, 1/4W resistors. 1% resistors are not much more expensive than 5% and can be be handy when you need to adjust the gain of an op-amp or trim the output of an adjustable regulator. Usually it makes sense to purchase a kit of resistors with five to ten of each value. As you run out of common values (like 1K, 10K, etc) restock those values by buying 100 pieces. If a reasonably priced kit is not available I would purchase the following values --
Description Digikey Link
100Ω MFR-25FBF-100R
124Ω (LM317 Trimming) MFR-25FBF-124R
205Ω (LM317 Trimming) MFR-25FBF-205R
374Ω (LM317 Trimming) MFR-25FBF-374R
475Ω MFR-25FBF-475R
1KΩ MFR-25FBF-1K00
4.75KΩ MFR-25FBF-4K75
9.09KΩ MFR-25FBF-9K09
10KΩ MFR-25FBF-10K0
90.9KΩ MFR-25FBF-90K9
100KΩ MFR-25FBF-100K
Trim Pots
Description Digikey Link
Trim Pot 200Ohms (useful for LM317T trimming) PV36W201C01B00
Trim Pot 10KOhms PV36W103C01B00
Capacitors
For capacitors up to 1µF I would use ceramic capacitors. They are reasonable priced and non-polarized. I would purchase X7R (or X5R) type capacitors for values from 1000pF to 1µF and NP0 type capacitors for values below 1000pF. Some common values --
Description Digikey Link
33pF, 50V, NP0 AVX AR215A330K4R
100pF, 50V, NP0 AVX AR215A101K4R
1000pF, 50V, NP0 AVX AR155A102K4R
4700pF X7R B37981F5472K051
10000pF X7R B37981F5103K051
47000pF X7R B37981F5473K051
0.1uF X7R B37981M5104K051
0.47uF X7R FK26X7R1H474K
1uF X7R FK20X7R1H105K
10uF, 25V Electrolytic, Low ESR UPW1E100MDD
100uF, 25V Electrolytic, Low ESR UPW1E101MED
法拉电容（超级电容）
Connectors
Coming Soon
Wire
UL1050 PVC Insulated Wire
Thick insulation, 30AWG strands. Good for crimps.
UL1213 High Temperature Teflon Insulated Hookup Wire
Teflon insulation won't melt when soldering, 30AWG to 38AWG
Uninsulated Buss Wire
The sizes I find most useful are 22AWG, 24AWG, 28AWG
Teflon Tubing
Goes over the uninsulated buss wire
